diff --git a/.ncrunch/Avalonia.Direct2D1.RenderTests.v3.ncrunchproject b/.ncrunch/Avalonia.Direct2D1.RenderTests.v3.ncrunchproject
index a8c3abe8f2..04ab17c4e1 100644
--- a/.ncrunch/Avalonia.Direct2D1.RenderTests.v3.ncrunchproject
+++ b/.ncrunch/Avalonia.Direct2D1.RenderTests.v3.ncrunchproject
@@ -1,7 +1,6 @@
 <ProjectConfiguration>
   <Settings>
-    <DefaultTestTimeout>1000</DefaultTestTimeout>
-    <IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely>
+    <DefaultTestTimeout>3000</DefaultTestTimeout>
     <PreviouslyBuiltSuccessfully>True</PreviouslyBuiltSuccessfully>
   </Settings>
 </ProjectConfiguration>
\ No newline at end of file
diff --git a/Avalonia.sln b/Avalonia.sln
index c6509817ce..a29f3dd754 100644
--- a/Avalonia.sln
+++ b/Avalonia.sln
@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
-VisualStudioVersion = 15.0.26730.10
+VisualStudioVersion = 15.0.27004.2008
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Avalonia.Base", "src\Avalonia.Base\Avalonia.Base.csproj", "{B09B78D8-9B26-48B0-9149-D64A2F120F3F}"
 EndProject
@@ -155,7 +155,6 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Props", "Props", "{F3AC8BC1
 		build\ReactiveUI.props = build\ReactiveUI.props
 		build\Rx.props = build\Rx.props
 		build\Serilog.props = build\Serilog.props
-		build\Serilog.Sinks.Trace.props = build\Serilog.Sinks.Trace.props
 		build\SharpDX.props = build\SharpDX.props
 		build\SkiaSharp.Desktop.props = build\SkiaSharp.Desktop.props
 		build\SkiaSharp.props = build\SkiaSharp.props
diff --git a/appveyor.yml b/appveyor.yml
index 76d1ae3e1c..ba3680d0b9 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,4 +1,4 @@
-os: Visual Studio 2017
+os: Previous Visual Studio 2017
 platform:
 - Any CPU
 skip_branch_with_pr: true
diff --git a/build/MonoMac.props b/build/MonoMac.props
index 452177ca5d..5cf19ef503 100644
--- a/build/MonoMac.props
+++ b/build/MonoMac.props
@@ -1,5 +1,5 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="MonoMac.NetStandard" Version="0.0.3" />
+    <PackageReference Include="MonoMac.NetStandard" Version="0.0.4" />
   </ItemGroup>
 </Project>
diff --git a/build/Serilog.Sinks.Trace.props b/build/Serilog.Sinks.Trace.props
deleted file mode 100644
index ef79fd7669..0000000000
--- a/build/Serilog.Sinks.Trace.props
+++ /dev/null
@@ -1,5 +0,0 @@
-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <ItemGroup>
-     <PackageReference Include="Serilog.Sinks.Trace" Version="2.1.0" />
-  </ItemGroup>
-</Project>
diff --git a/build/Serilog.props b/build/Serilog.props
index e9bd39f6af..a814cf998d 100644
--- a/build/Serilog.props
+++ b/build/Serilog.props
@@ -1,5 +1,7 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-     <PackageReference Include="Serilog" Version="2.4.0" />
+    <PackageReference Include="Serilog" Version="2.5.0" />
+    <PackageReference Include="Serilog.Sinks.Trace" Version="2.1.0" />
+    <PackageReference Include="Serilog.Sinks.Debug" Version="1.0.0" />
   </ItemGroup>
 </Project>
diff --git a/packages.cake b/packages.cake
index 9e78ee75d5..bc290fce22 100644
--- a/packages.cake
+++ b/packages.cake
@@ -107,6 +107,8 @@ public class Packages
         context.Information("Setting NuGet package dependencies versions:");
 
         var SerilogVersion = packageVersions["Serilog"].FirstOrDefault().Item1;
+        var SerilogSinksDebugVersion = packageVersions["Serilog.Sinks.Debug"].FirstOrDefault().Item1;
+        var SerilogSinksTraceVersion = packageVersions["Serilog.Sinks.Trace"].FirstOrDefault().Item1;
         var SpracheVersion = packageVersions["Sprache"].FirstOrDefault().Item1;
         var SystemReactiveVersion = packageVersions["System.Reactive"].FirstOrDefault().Item1;
         var ReactiveUIVersion = packageVersions["reactiveui"].FirstOrDefault().Item1;
@@ -243,6 +245,8 @@ public class Packages
                 Dependencies = new DependencyBuilder(this)
                 {
                     new NuSpecDependency() { Id = "Serilog", Version = SerilogVersion },
+                    new NuSpecDependency() { Id = "Serilog.Sinks.Debug", Version = SerilogSinksDebugVersion },
+                    new NuSpecDependency() { Id = "Serilog.Sinks.Trace", Version = SerilogSinksTraceVersion },
                     new NuSpecDependency() { Id = "Sprache", Version = SpracheVersion },
                     new NuSpecDependency() { Id = "System.Reactive", Version = SystemReactiveVersion },
                     new NuSpecDependency() { Id = "Avalonia.Remote.Protocol", Version = parameters.Version },
@@ -251,6 +255,8 @@ public class Packages
                     new NuSpecDependency() { Id = "Microsoft.Extensions.DependencyModel", TargetFramework = "netcoreapp2.0", Version = "1.1.0" },
                     new NuSpecDependency() { Id = "NETStandard.Library", TargetFramework = "netcoreapp2.0", Version = "1.6.0" },
                     new NuSpecDependency() { Id = "Serilog", TargetFramework = "netcoreapp2.0", Version = SerilogVersion },
+                    new NuSpecDependency() { Id = "Serilog.Sinks.Debug", TargetFramework = "netcoreapp2.0", Version = SerilogSinksDebugVersion },
+                    new NuSpecDependency() { Id = "Serilog.Sinks.Trace", TargetFramework = "netcoreapp2.0", Version = SerilogSinksTraceVersion },
                     new NuSpecDependency() { Id = "Sprache", TargetFramework = "netcoreapp2.0", Version = SpracheVersion },
                     new NuSpecDependency() { Id = "System.Reactive", TargetFramework = "netcoreapp2.0", Version = SystemReactiveVersion },
                     new NuSpecDependency() { Id = "Avalonia.Remote.Protocol", TargetFramework = "netcoreapp2.0", Version = parameters.Version },
diff --git a/samples/BindingTest/App.xaml.cs b/samples/BindingTest/App.xaml.cs
index 42e5716541..ccad1d0ba9 100644
--- a/samples/BindingTest/App.xaml.cs
+++ b/samples/BindingTest/App.xaml.cs
@@ -16,22 +16,11 @@ namespace BindingTest
 
         private static void Main()
         {
-            InitializeLogging();
-
             AppBuilder.Configure<App>()
                 .UsePlatformDetect()
                 .UseReactiveUI()
+                .LogToDebug()
                 .Start<MainWindow>();
         }
-
-        private static void InitializeLogging()
-        {
-#if DEBUG
-            SerilogLogger.Initialize(new LoggerConfiguration()
-                .MinimumLevel.Warning()
-                .WriteTo.Trace(outputTemplate: "{Area}: {Message}")
-                .CreateLogger());
-#endif
-        }
     }
 }
diff --git a/samples/BindingTest/BindingTest.csproj b/samples/BindingTest/BindingTest.csproj
index 4f82303c3a..9f3fed5522 100644
--- a/samples/BindingTest/BindingTest.csproj
+++ b/samples/BindingTest/BindingTest.csproj
@@ -151,7 +151,6 @@
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <Import Project="..\..\build\Serilog.props" />
-  <Import Project="..\..\build\Serilog.Sinks.Trace.props" />
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\ReactiveUI.props" />
 </Project>
\ No newline at end of file
diff --git a/samples/ControlCatalog.Desktop/ControlCatalog.Desktop.csproj b/samples/ControlCatalog.Desktop/ControlCatalog.Desktop.csproj
index 3f4679086e..cfa2f89b0e 100644
--- a/samples/ControlCatalog.Desktop/ControlCatalog.Desktop.csproj
+++ b/samples/ControlCatalog.Desktop/ControlCatalog.Desktop.csproj
@@ -135,5 +135,4 @@
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <Import Project="..\..\build\Serilog.props" />
   <Import Project="..\..\build\SkiaSharp.props" />
-  <Import Project="..\..\build\Serilog.Sinks.Trace.props" />
 </Project>
\ No newline at end of file
diff --git a/samples/ControlCatalog.Desktop/Program.cs b/samples/ControlCatalog.Desktop/Program.cs
index 20bf4ed342..b151cabf43 100644
--- a/samples/ControlCatalog.Desktop/Program.cs
+++ b/samples/ControlCatalog.Desktop/Program.cs
@@ -12,8 +12,6 @@ namespace ControlCatalog
     {
         static void Main(string[] args)
         {
-            InitializeLogging();
-
             // TODO: Make this work with GTK/Skia/Cairo depending on command-line args
             // again.
             BuildAvaloniaApp().Start<MainWindow>();
@@ -23,18 +21,7 @@ namespace ControlCatalog
         /// This method is needed for IDE previewer infrastructure
         /// </summary>
         public static AppBuilder BuildAvaloniaApp()
-            => AppBuilder.Configure<App>().UsePlatformDetect();
-
-        // This will be made into a runtime configuration extension soon!
-        private static void InitializeLogging()
-        {
-#if DEBUG
-            SerilogLogger.Initialize(new LoggerConfiguration()
-                .MinimumLevel.Warning()
-                .WriteTo.Trace(outputTemplate: "{Area}: {Message}")
-                .CreateLogger());
-#endif
-        }
+            => AppBuilder.Configure<App>().LogToDebug().UsePlatformDetect();
 
         private static void ConfigureAssetAssembly(AppBuilder builder)
         {
diff --git a/samples/ControlCatalog/ControlCatalog.csproj b/samples/ControlCatalog/ControlCatalog.csproj
index 11ff531514..0b4463ddb7 100644
--- a/samples/ControlCatalog/ControlCatalog.csproj
+++ b/samples/ControlCatalog/ControlCatalog.csproj
@@ -44,6 +44,9 @@
     <EmbeddedResource Include="Pages\ButtonPage.xaml">
       <SubType>Designer</SubType>
     </EmbeddedResource>
+    <EmbeddedResource Include="Pages\CalendarPage.xaml">
+      <SubType>Designer</SubType>
+    </EmbeddedResource>
     <EmbeddedResource Include="Pages\CanvasPage.xaml">
       <SubType>Designer</SubType>
     </EmbeddedResource>
@@ -107,6 +110,9 @@
     <Compile Include="Pages\ButtonPage.xaml.cs">
       <DependentUpon>ButtonPage.xaml</DependentUpon>
     </Compile>
+    <Compile Include="Pages\CalendarPage.xaml.cs">
+      <DependentUpon>CalendarPage.xaml</DependentUpon>
+    </Compile>
     <Compile Include="Pages\CanvasPage.xaml.cs">
       <DependentUpon>CanvasPage.xaml</DependentUpon>
     </Compile>
diff --git a/samples/ControlCatalog/MainView.xaml b/samples/ControlCatalog/MainView.xaml
index 0940316ce9..311a61a6dc 100644
--- a/samples/ControlCatalog/MainView.xaml
+++ b/samples/ControlCatalog/MainView.xaml
@@ -7,6 +7,7 @@
     </TabControl.Transition>
     <TabItem Header="Border"><pages:BorderPage/></TabItem>
     <TabItem Header="Button"><pages:ButtonPage/></TabItem>
+    <TabItem Header="Calendar"><pages:CalendarPage/></TabItem>
     <TabItem Header="Canvas"><pages:CanvasPage/></TabItem>
     <TabItem Header="Carousel"><pages:CarouselPage/></TabItem>
     <TabItem Header="CheckBox"><pages:CheckBoxPage/></TabItem>
diff --git a/samples/ControlCatalog/Pages/CalendarPage.xaml b/samples/ControlCatalog/Pages/CalendarPage.xaml
new file mode 100644
index 0000000000..a433fd1add
--- /dev/null
+++ b/samples/ControlCatalog/Pages/CalendarPage.xaml
@@ -0,0 +1,47 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+  <StackPanel Orientation="Vertical" Gap="4">
+    <TextBlock Classes="h1">Calendar</TextBlock>
+    <TextBlock Classes="h2">A calendar control for selecting dates</TextBlock>
+        
+    <StackPanel Orientation="Horizontal"
+                Margin="0,16,0,0"
+                HorizontalAlignment="Center"
+                Gap="16">
+      <StackPanel Orientation="Vertical">
+        <TextBlock Text="SelectionMode: None"/>
+        <Calendar SelectionMode="None"
+                  Margin="0,0,0,8"/>
+
+        <TextBlock Text="SelectionMode: SingleDate"/>
+        <Calendar SelectionMode="SingleDate"
+                  Margin="0,0,0,8"/>
+
+        <TextBlock Text="Disabled"/>
+        <Calendar IsEnabled="False"
+                  SelectionMode="SingleDate"/>
+      </StackPanel>
+
+      <StackPanel Orientation="Vertical">
+        <TextBlock Text="SelectionMode: SingleRange"/>
+        <Calendar SelectionMode="SingleRange"
+                  Margin="0,0,0,8"/>
+
+        <TextBlock Text="SelectionMode: MultipleRange"/>
+        <Calendar SelectionMode="MultipleRange"/>
+      </StackPanel>
+
+      <StackPanel Orientation="Vertical">
+        <TextBlock Text="DisplayDates"/>
+        <Calendar Name="DisplayDatesCalendar"
+                  SelectionMode="SingleDate"
+                  Margin="0,0,0,8"/>
+
+        <TextBlock Text="BlackoutDates"/>
+        <Calendar Name="BlackoutDatesCalendar"
+                  SelectionMode="SingleDate" />
+      </StackPanel>
+      
+    </StackPanel> 
+  </StackPanel>
+</UserControl>
\ No newline at end of file
diff --git a/samples/ControlCatalog/Pages/CalendarPage.xaml.cs b/samples/ControlCatalog/Pages/CalendarPage.xaml.cs
new file mode 100644
index 0000000000..e3e9a3444e
--- /dev/null
+++ b/samples/ControlCatalog/Pages/CalendarPage.xaml.cs
@@ -0,0 +1,28 @@
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+using System;
+
+namespace ControlCatalog.Pages
+{
+    public class CalendarPage : UserControl
+    {
+        public CalendarPage()
+        {
+            this.InitializeComponent();
+
+            var today = DateTime.Today; 
+            var cal1 = this.FindControl<Calendar>("DisplayDatesCalendar");
+            cal1.DisplayDateStart = today.AddDays(-25);
+            cal1.DisplayDateEnd = today.AddDays(25);
+
+            var cal2 = this.FindControl<Calendar>("BlackoutDatesCalendar");
+            cal2.BlackoutDates.AddDatesInPast();
+            cal2.BlackoutDates.Add(new CalendarDateRange(today.AddDays(6)));
+        }
+
+        private void InitializeComponent()
+        {
+            AvaloniaXamlLoader.Load(this);
+        }
+    }
+}
diff --git a/samples/ControlCatalog/Pages/CarouselPage.xaml b/samples/ControlCatalog/Pages/CarouselPage.xaml
index 317159cd8d..4a5b2cea26 100644
--- a/samples/ControlCatalog/Pages/CarouselPage.xaml
+++ b/samples/ControlCatalog/Pages/CarouselPage.xaml
@@ -9,7 +9,7 @@
       </Button>
       <Carousel Name="carousel">
         <Carousel.Transition>
-          <PageSlide Duration="0.25"/>
+          <PageSlide Duration="0.25" Orientation="Vertical" />
         </Carousel.Transition>
         <Image Source="resm:ControlCatalog.Assets.delicate-arch-896885_640.jpg"/>
         <Image Source="resm:ControlCatalog.Assets.hirsch-899118_640.jpg"/>
@@ -28,6 +28,14 @@
         <DropDownItem>Crossfade</DropDownItem>
       </DropDown>
     </StackPanel>
+
+    <StackPanel Orientation="Horizontal" Gap="4">
+      <TextBlock VerticalAlignment="Center">Orientation</TextBlock>
+      <DropDown Name="orientation" SelectedIndex="1" VerticalAlignment="Center">
+        <DropDownItem>Horizontal</DropDownItem>
+        <DropDownItem>Vertical</DropDownItem>
+      </DropDown>
+    </StackPanel>
     
   </StackPanel>
 </UserControl>
\ No newline at end of file
diff --git a/samples/ControlCatalog/Pages/CarouselPage.xaml.cs b/samples/ControlCatalog/Pages/CarouselPage.xaml.cs
index 1c408c8ed7..272290e679 100644
--- a/samples/ControlCatalog/Pages/CarouselPage.xaml.cs
+++ b/samples/ControlCatalog/Pages/CarouselPage.xaml.cs
@@ -11,6 +11,7 @@ namespace ControlCatalog.Pages
         private Button _left;
         private Button _right;
         private DropDown _transition;
+        private DropDown _orientation;
 
         public CarouselPage()
         {
@@ -18,6 +19,7 @@ namespace ControlCatalog.Pages
             _left.Click += (s, e) => _carousel.Previous();
             _right.Click += (s, e) => _carousel.Next();
             _transition.SelectionChanged += TransitionChanged;
+            _orientation.SelectionChanged += TransitionChanged;
         }
 
         private void InitializeComponent()
@@ -27,6 +29,7 @@ namespace ControlCatalog.Pages
             _left = this.FindControl<Button>("left");
             _right = this.FindControl<Button>("right");
             _transition = this.FindControl<DropDown>("transition");
+            _orientation = this.FindControl<DropDown>("orientation");
         }
 
         private void TransitionChanged(object sender, SelectionChangedEventArgs e)
@@ -37,7 +40,7 @@ namespace ControlCatalog.Pages
                     _carousel.Transition = null;
                     break;
                 case 1:
-                    _carousel.Transition = new PageSlide(TimeSpan.FromSeconds(0.25));
+                    _carousel.Transition = new PageSlide(TimeSpan.FromSeconds(0.25), _orientation.SelectedIndex == 0 ? PageSlide.SlideAxis.Horizontal : PageSlide.SlideAxis.Vertical);
                     break;
                 case 2:
                     _carousel.Transition = new CrossFade(TimeSpan.FromSeconds(0.25));
diff --git a/samples/ControlCatalog/Pages/CheckBoxPage.xaml b/samples/ControlCatalog/Pages/CheckBoxPage.xaml
index 4a6db5bed9..a00b3a7bef 100644
--- a/samples/ControlCatalog/Pages/CheckBoxPage.xaml
+++ b/samples/ControlCatalog/Pages/CheckBoxPage.xaml
@@ -1,15 +1,28 @@
-<UserControl xmlns="https://github.com/avaloniaui">
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <StackPanel Orientation="Vertical" Gap="4">
     <TextBlock Classes="h1">CheckBox</TextBlock>
     <TextBlock Classes="h2">A check box control</TextBlock>
 
-    <StackPanel Orientation="Vertical"
+    <StackPanel Orientation="Horizontal"
                 Margin="0,16,0,0"
                 HorizontalAlignment="Center"
                 Gap="16">
-      <CheckBox>Unchecked</CheckBox>
-      <CheckBox IsChecked="True">Checked</CheckBox>
-      <CheckBox IsChecked="True" IsEnabled="False">Disabled</CheckBox>
-    </StackPanel>    
+      <StackPanel Orientation="Vertical"
+                  Gap="16">
+        <CheckBox>Unchecked</CheckBox>
+        <CheckBox IsChecked="True">Checked</CheckBox>
+        <CheckBox IsChecked="{x:Null}">Indeterminate</CheckBox>
+        <CheckBox IsChecked="True" IsEnabled="False">Disabled</CheckBox>
+      </StackPanel>
+      <StackPanel Orientation="Vertical"
+                  HorizontalAlignment="Center"
+                  Gap="16">
+        <CheckBox IsChecked="False" IsThreeState="True">Three State: Unchecked</CheckBox>
+        <CheckBox IsChecked="True" IsThreeState="True">Three State: Checked</CheckBox>
+        <CheckBox IsChecked="{x:Null}" IsThreeState="True">Three State: Indeterminate</CheckBox>
+        <CheckBox IsChecked="{x:Null}" IsThreeState="True" IsEnabled="False">Three State: Disabled</CheckBox>
+      </StackPanel>
+    </StackPanel>
   </StackPanel>
 </UserControl>
\ No newline at end of file
diff --git a/samples/ControlCatalog/Pages/DialogsPage.xaml.cs b/samples/ControlCatalog/Pages/DialogsPage.xaml.cs
index 94364da698..8b3e810f0a 100644
--- a/samples/ControlCatalog/Pages/DialogsPage.xaml.cs
+++ b/samples/ControlCatalog/Pages/DialogsPage.xaml.cs
@@ -36,7 +36,7 @@ namespace ControlCatalog.Pages
             };
         }
 
-        Window GetWindow() => this.FindControl<CheckBox>("IsModal").IsChecked ? (Window)this.VisualRoot : null;
+        Window GetWindow() => this.FindControl<CheckBox>("IsModal").IsChecked.Value ? (Window)this.VisualRoot : null;
 
         private void InitializeComponent()
         {
diff --git a/samples/ControlCatalog/Pages/RadioButtonPage.xaml b/samples/ControlCatalog/Pages/RadioButtonPage.xaml
index a40477a679..d382b94f2c 100644
--- a/samples/ControlCatalog/Pages/RadioButtonPage.xaml
+++ b/samples/ControlCatalog/Pages/RadioButtonPage.xaml
@@ -1,15 +1,27 @@
-<UserControl xmlns="https://github.com/avaloniaui">
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <StackPanel Orientation="Vertical" Gap="4">
     <TextBlock Classes="h1">RadioButton</TextBlock>
     <TextBlock Classes="h2">Allows the selection of a single option of many</TextBlock>
 
-    <StackPanel Orientation="Vertical"
+    <StackPanel Orientation="Horizontal"
                 Margin="0,16,0,0"
                 HorizontalAlignment="Center"
                 Gap="16">
-      <RadioButton IsChecked="True">Option 1</RadioButton>
-      <RadioButton>Option 2</RadioButton>
-      <RadioButton IsEnabled="False">Disabled</RadioButton>
-    </StackPanel>    
+      <StackPanel Orientation="Vertical"
+                  Gap="16">
+        <RadioButton IsChecked="True">Option 1</RadioButton>
+        <RadioButton>Option 2</RadioButton>
+        <RadioButton IsChecked="{x:Null}">Option 3</RadioButton>
+        <RadioButton IsEnabled="False">Disabled</RadioButton>
+      </StackPanel>
+      <StackPanel Orientation="Vertical"
+                  Gap="16">
+        <RadioButton IsChecked="True" IsThreeState="True">Three States: Option 1</RadioButton>
+        <RadioButton IsChecked="False" IsThreeState="True">Three States: Option 2</RadioButton>
+        <RadioButton IsChecked="{x:Null}" IsThreeState="True">Three States: Option 3</RadioButton>
+        <RadioButton IsChecked="{x:Null}" IsThreeState="True" IsEnabled="False">Disabled</RadioButton>
+      </StackPanel>
+    </StackPanel>
   </StackPanel>
 </UserControl>
\ No newline at end of file
diff --git a/samples/RenderTest/Program.cs b/samples/RenderTest/Program.cs
index 514771097f..a1a2b8c410 100644
--- a/samples/RenderTest/Program.cs
+++ b/samples/RenderTest/Program.cs
@@ -12,25 +12,13 @@ namespace RenderTest
     {
         static void Main(string[] args)
         {
-            InitializeLogging();
-
             // TODO: Make this work with GTK/Skia/Cairo depending on command-line args
             // again.
             AppBuilder.Configure<App>()
                 .UsePlatformDetect()
                 .UseReactiveUI()
+                .LogToDebug()
                 .Start<MainWindow>();
         }
-
-        // This will be made into a runtime configuration extension soon!
-        private static void InitializeLogging()
-        {
-#if DEBUG
-            SerilogLogger.Initialize(new LoggerConfiguration()
-                .MinimumLevel.Warning()
-                .WriteTo.Trace(outputTemplate: "{Area}: {Message}")
-                .CreateLogger());
-#endif
-        }
     }
 }
diff --git a/samples/RenderTest/RenderTest.csproj b/samples/RenderTest/RenderTest.csproj
index a71f17ab7a..4a471a831a 100644
--- a/samples/RenderTest/RenderTest.csproj
+++ b/samples/RenderTest/RenderTest.csproj
@@ -180,7 +180,6 @@
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <Import Project="..\..\build\Serilog.props" />
-  <Import Project="..\..\build\Serilog.Sinks.Trace.props" />
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\ReactiveUI.props" />
 </Project>
\ No newline at end of file
diff --git a/samples/VirtualizationTest/Program.cs b/samples/VirtualizationTest/Program.cs
index e9156d803f..097f0cfdc7 100644
--- a/samples/VirtualizationTest/Program.cs
+++ b/samples/VirtualizationTest/Program.cs
@@ -13,22 +13,11 @@ namespace VirtualizationTest
     {
         static void Main(string[] args)
         {
-            InitializeLogging();
-
             AppBuilder.Configure<App>()
                .UsePlatformDetect()
                .UseReactiveUI()
+               .LogToDebug()
                .Start<MainWindow>();
         }
-
-        private static void InitializeLogging()
-        {
-#if DEBUG
-            SerilogLogger.Initialize(new LoggerConfiguration()
-                .MinimumLevel.Warning()
-                .WriteTo.Trace(outputTemplate: "{Area}: {Message}")
-                .CreateLogger());
-#endif
-        }
     }
 }
diff --git a/samples/VirtualizationTest/VirtualizationTest.csproj b/samples/VirtualizationTest/VirtualizationTest.csproj
index 6d3803b4cf..147355aed1 100644
--- a/samples/VirtualizationTest/VirtualizationTest.csproj
+++ b/samples/VirtualizationTest/VirtualizationTest.csproj
@@ -147,7 +147,6 @@
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <Import Project="..\..\build\Serilog.props" />
-  <Import Project="..\..\build\Serilog.Sinks.Trace.props" />
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\ReactiveUI.props" />
 </Project>
\ No newline at end of file
diff --git a/samples/interop/Direct3DInteropSample/Direct3DInteropSample.csproj b/samples/interop/Direct3DInteropSample/Direct3DInteropSample.csproj
index e0fc79faea..4271d05f91 100644
--- a/samples/interop/Direct3DInteropSample/Direct3DInteropSample.csproj
+++ b/samples/interop/Direct3DInteropSample/Direct3DInteropSample.csproj
@@ -28,6 +28,5 @@
         <ProjectReference Include="..\..\..\src\Windows\Avalonia.Win32\Avalonia.Win32.csproj" />
     </ItemGroup>
     <Import Project="..\..\..\build\Serilog.props" />
-    <Import Project="..\..\..\build\Serilog.Sinks.Trace.props" />
     <Import Project="..\..\..\build\Rx.props" />
 </Project>
\ No newline at end of file
diff --git a/scripts/ReplaceNugetCache.ps1 b/scripts/ReplaceNugetCache.ps1
index 4ad31db274..a03d442bff 100644
--- a/scripts/ReplaceNugetCache.ps1
+++ b/scripts/ReplaceNugetCache.ps1
@@ -2,3 +2,4 @@ copy ..\samples\ControlCatalog.NetCore\bin\Debug\netcoreapp2.0\Avalonia**.dll ~\
 copy ..\samples\ControlCatalog.NetCore.\bin\Debug\netcoreapp2.0\Avalonia**.dll ~\.nuget\packages\avalonia\$args\lib\netstandard2.0\
 copy ..\samples\ControlCatalog.NetCore.\bin\Debug\netcoreapp2.0\Avalonia**.dll ~\.nuget\packages\avalonia.gtk3\$args\lib\netstandard2.0\
 copy ..\samples\ControlCatalog.NetCore.\bin\Debug\netcoreapp2.0\Avalonia**.dll ~\.nuget\packages\avalonia.win32\$args\lib\netstandard2.0\
+copy ..\samples\ControlCatalog.NetCore.\bin\Debug\netcoreapp2.0\Avalonia**.dll ~\.nuget\packages\avalonia.skia\$args\lib\netstandard2.0\
diff --git a/scripts/ReplaceNugetCache.sh b/scripts/ReplaceNugetCache.sh
index 636aec5f23..d50f4152e8 100755
--- a/scripts/ReplaceNugetCache.sh
+++ b/scripts/ReplaceNugetCache.sh
@@ -3,4 +3,6 @@
  cp ../samples/ControlCatalog.NetCore/bin/Debug/netcoreapp2.0/Avalonia**.dll ~/.nuget/packages/avalonia/$1/lib/netcoreapp2.0/
  cp ../samples/ControlCatalog.NetCore/bin/Debug/netcoreapp2.0/Avalonia**.dll ~/.nuget/packages/avalonia/$1/lib/netstandard2.0/
  cp ../samples/ControlCatalog.NetCore/bin/Debug/netcoreapp2.0/Avalonia**.dll ~/.nuget/packages/avalonia.gtk3/$1/lib/netstandard2.0/
+ cp ../samples/ControlCatalog.NetCore/bin/Debug/netcoreapp2.0/Avalonia**.dll ~/.nuget/packages/avalonia.skia/$1/lib/netstandard2.0/
+ 
  
diff --git a/scripts/ReplaceNugetCacheRelease.ps1 b/scripts/ReplaceNugetCacheRelease.ps1
index f188c81c51..1c19e00400 100644
--- a/scripts/ReplaceNugetCacheRelease.ps1
+++ b/scripts/ReplaceNugetCacheRelease.ps1
@@ -1,4 +1,5 @@
 copy ..\samples\ControlCatalog.NetCore\bin\Release\netcoreapp2.0\Avalonia**.dll ~\.nuget\packages\avalonia\$args\lib\netcoreapp2.0\
 copy ..\samples\ControlCatalog.NetCore.\bin\Release\netcoreapp2.0\Avalonia**.dll ~\.nuget\packages\avalonia\$args\lib\netstandard2.0\
 copy ..\samples\ControlCatalog.NetCore.\bin\Release\netcoreapp2.0\Avalonia**.dll ~\.nuget\packages\avalonia.gtk3\$args\lib\netstandard2.0\
-copy ..\samples\ControlCatalog.NetCore.\bin\Release\netcoreapp2.0\Avalonia**.dll ~\.nuget\packages\avalonia.win32\$args\lib\netstandard2.0\
\ No newline at end of file
+copy ..\samples\ControlCatalog.NetCore.\bin\Release\netcoreapp2.0\Avalonia**.dll ~\.nuget\packages\avalonia.win32\$args\lib\netstandard2.0\
+copy ..\samples\ControlCatalog.NetCore.\bin\Release\netcoreapp2.0\Avalonia**.dll ~\.nuget\packages\avalonia.skia\$args\lib\netstandard2.0\
\ No newline at end of file
diff --git a/src/Android/Avalonia.AndroidTestApplication/MainActivity.cs b/src/Android/Avalonia.AndroidTestApplication/MainActivity.cs
index 7973ad72e5..ad2cec2ae3 100644
--- a/src/Android/Avalonia.AndroidTestApplication/MainActivity.cs
+++ b/src/Android/Avalonia.AndroidTestApplication/MainActivity.cs
@@ -56,7 +56,7 @@ namespace Avalonia.AndroidTestApplication
                 {
                     Margin = new Thickness(30),
                     Background = Brushes.Yellow,
-                    Children = new Avalonia.Controls.Controls
+                    Children =
                     {
                         new TextBlock
                         {
diff --git a/src/Avalonia.Animation/Avalonia.Animation.csproj b/src/Avalonia.Animation/Avalonia.Animation.csproj
index bafac2b261..2101c5669d 100644
--- a/src/Avalonia.Animation/Avalonia.Animation.csproj
+++ b/src/Avalonia.Animation/Avalonia.Animation.csproj
@@ -11,7 +11,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Animation.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Animation.xml</DocumentationFile>
     <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
@@ -21,7 +21,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Animation.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Animation.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
diff --git a/src/Avalonia.Base/Avalonia.Base.csproj b/src/Avalonia.Base/Avalonia.Base.csproj
index 58c510f483..54537841a9 100644
--- a/src/Avalonia.Base/Avalonia.Base.csproj
+++ b/src/Avalonia.Base/Avalonia.Base.csproj
@@ -12,7 +12,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Base.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Base.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
@@ -22,7 +22,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Base.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Base.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
diff --git a/src/Avalonia.Base/AvaloniaObject.cs b/src/Avalonia.Base/AvaloniaObject.cs
index efcbb57244..17e6ea8f0f 100644
--- a/src/Avalonia.Base/AvaloniaObject.cs
+++ b/src/Avalonia.Base/AvaloniaObject.cs
@@ -51,6 +51,21 @@ namespace Avalonia
         /// </summary>
         private EventHandler<AvaloniaPropertyChangedEventArgs> _propertyChanged;
 
+        private DeferredSetter<AvaloniaProperty, object> _directDeferredSetter;
+
+        /// <summary>
+        /// Delayed setter helper for direct properties. Used to fix #855.
+        /// </summary>
+        private DeferredSetter<AvaloniaProperty, object> DirectPropertyDeferredSetter
+        {
+            get
+            {
+                return _directDeferredSetter ??
+                    (_directDeferredSetter = new DeferredSetter<AvaloniaProperty, object>());
+            }
+        }
+
+
         /// <summary>
         /// Initializes a new instance of the <see cref="AvaloniaObject"/> class.
         /// </summary>
@@ -225,6 +240,19 @@ namespace Avalonia
             return (T)GetValue((AvaloniaProperty)property);
         }
 
+        /// <summary>
+        /// Checks whether a <see cref="AvaloniaProperty"/> is animating.
+        /// </summary>
+        /// <param name="property">The property.</param>
+        /// <returns>True if the property is animating, otherwise false.</returns>
+        public bool IsAnimating(AvaloniaProperty property)
+        {
+            Contract.Requires<ArgumentNullException>(property != null);
+            VerifyAccess();
+
+            return _values.TryGetValue(property, out PriorityValue value) ? value.IsAnimating : false;
+        }
+
         /// <summary>
         /// Checks whether a <see cref="AvaloniaProperty"/> is set on this object.
         /// </summary>
@@ -311,9 +339,6 @@ namespace Avalonia
 
             var description = GetDescription(source);
 
-            var scheduler = AvaloniaLocator.Current.GetService<IScheduler>() ?? ImmediateScheduler.Instance;
-            source = source.ObserveOn(scheduler); 
-
             if (property.IsDirect)
             {
                 if (property.IsReadOnly)
@@ -539,6 +564,45 @@ namespace Avalonia
             }
         }
 
+        /// <summary>
+        /// A callback type for encapsulating complex logic for setting direct properties.
+        /// </summary>
+        /// <typeparam name="T">The type of the property.</typeparam>
+        /// <param name="value">The value to which to set the property.</param>
+        /// <param name="field">The backing field for the property.</param>
+        /// <param name="notifyWrapper">A wrapper for the property-changed notification.</param>
+        protected delegate void SetAndRaiseCallback<T>(T value, ref T field, Action<Action> notifyWrapper);
+
+        /// <summary>
+        /// Sets the backing field for a direct avalonia property, raising the 
+        /// <see cref="PropertyChanged"/> event if the value has changed.
+        /// </summary>
+        /// <typeparam name="T">The type of the property.</typeparam>
+        /// <param name="property">The property.</param>
+        /// <param name="field">The backing field.</param>
+        /// <param name="setterCallback">A callback called to actually set the value to the backing field.</param>
+        /// <param name="value">The value.</param>
+        /// <returns>
+        /// True if the value changed, otherwise false.
+        /// </returns>
+        protected bool SetAndRaise<T>(
+            AvaloniaProperty<T> property,
+            ref T field,
+            SetAndRaiseCallback<T> setterCallback,
+            T value)
+        {
+            Contract.Requires<ArgumentNullException>(setterCallback != null);
+            return DirectPropertyDeferredSetter.SetAndNotify(
+                property,
+                ref field,
+                (object val, ref T backing, Action<Action> notify) =>
+                {
+                    setterCallback((T)val, ref backing, notify);
+                    return true;
+                },
+                value);
+        }
+
         /// <summary>
         /// Sets the backing field for a direct avalonia property, raising the 
         /// <see cref="PropertyChanged"/> event if the value has changed.
@@ -553,17 +617,32 @@ namespace Avalonia
         protected bool SetAndRaise<T>(AvaloniaProperty<T> property, ref T field, T value)
         {
             VerifyAccess();
-            if (!object.Equals(field, value))
-            {
-                var old = field;
-                field = value;
-                RaisePropertyChanged(property, old, value, BindingPriority.LocalValue);
-                return true;
-            }
-            else
-            {
-                return false;
-            }
+            return SetAndRaise(
+                property,
+                ref field,
+                (T val, ref T backing, Action<Action> notifyWrapper)
+                    => SetAndRaiseCore(property, ref backing, val, notifyWrapper),
+                value);
+        }
+
+        /// <summary>
+        /// Default assignment logic for SetAndRaise.
+        /// </summary>
+        /// <typeparam name="T">The type of the property.</typeparam>
+        /// <param name="property">The property.</param>
+        /// <param name="field">The backing field.</param>
+        /// <param name="value">The value.</param>
+        /// <param name="notifyWrapper">A wrapper for the property-changed notification.</param>
+        /// <returns>
+        /// True if the value changed, otherwise false.
+        /// </returns>
+        private bool SetAndRaiseCore<T>(AvaloniaProperty property, ref T field, T value, Action<Action> notifyWrapper)
+        {
+            var old = field;
+            field = value;
+
+            notifyWrapper(() => RaisePropertyChanged(property, old, value, BindingPriority.LocalValue));
+            return true;
         }
 
         /// <summary>
@@ -661,29 +740,41 @@ namespace Avalonia
         /// <param name="value">The value.</param>
         private void SetDirectValue(AvaloniaProperty property, object value)
         {
-            var notification = value as BindingNotification;
-
-            if (notification != null)
+            void Set()
             {
-                notification.LogIfError(this, property);
-                value = notification.Value;
-            }
+                var notification = value as BindingNotification;
 
-            if (notification == null || notification.ErrorType == BindingErrorType.Error || notification.HasValue)
-            {
-                var metadata = (IDirectPropertyMetadata)property.GetMetadata(GetType());
-                var accessor = (IDirectPropertyAccessor)GetRegistered(property);
-                var finalValue = value == AvaloniaProperty.UnsetValue ? 
-                    metadata.UnsetValue : value;
+                if (notification != null)
+                {
+                    notification.LogIfError(this, property);
+                    value = notification.Value;
+                }
 
-                LogPropertySet(property, value, BindingPriority.LocalValue);
+                if (notification == null || notification.ErrorType == BindingErrorType.Error || notification.HasValue)
+                {
+                    var metadata = (IDirectPropertyMetadata)property.GetMetadata(GetType());
+                    var accessor = (IDirectPropertyAccessor)GetRegistered(property);
+                    var finalValue = value == AvaloniaProperty.UnsetValue ?
+                        metadata.UnsetValue : value;
 
-                accessor.SetValue(this, finalValue);
+                    LogPropertySet(property, value, BindingPriority.LocalValue);
+
+                    accessor.SetValue(this, finalValue);
+                }
+
+                if (notification != null)
+                {
+                    UpdateDataValidation(property, notification);
+                }
             }
 
-            if (notification != null)
+            if (Dispatcher.UIThread.CheckAccess())
+            {
+                Set();
+            }
+            else
             {
-                UpdateDataValidation(property, notification);
+                Dispatcher.UIThread.InvokeAsync(Set);
             }
         }
 
diff --git a/src/Avalonia.Base/AvaloniaObjectExtensions.cs b/src/Avalonia.Base/AvaloniaObjectExtensions.cs
index e96679e643..1da2ecb942 100644
--- a/src/Avalonia.Base/AvaloniaObjectExtensions.cs
+++ b/src/Avalonia.Base/AvaloniaObjectExtensions.cs
@@ -138,17 +138,9 @@ namespace Avalonia
             AvaloniaProperty property,
             BindingPriority priority = BindingPriority.LocalValue)
         {
-            // TODO: Subject.Create<T> is not yet in stable Rx : once it is, remove the 
-            // AnonymousSubject classes and use Subject.Create<T>.
-            var output = new Subject<object>();
-            var result = new AnonymousSubject<object>(
-                Observer.Create<object>(
-                    x => output.OnNext(x),
-                    e => output.OnError(e),
-                    () => output.OnCompleted()),
+            return Subject.Create<object>(
+                Observer.Create<object>(x => o.SetValue(property, x, priority)),
                 o.GetObservable(property));
-            o.Bind(property, output, priority);
-            return result;
         }
 
         /// <summary>
@@ -169,17 +161,9 @@ namespace Avalonia
             AvaloniaProperty<T> property,
             BindingPriority priority = BindingPriority.LocalValue)
         {
-            // TODO: Subject.Create<T> is not yet in stable Rx : once it is, remove the 
-            // AnonymousSubject classes from this file and use Subject.Create<T>.
-            var output = new Subject<T>();
-            var result = new AnonymousSubject<T>(
-                Observer.Create<T>(
-                    x => output.OnNext(x),
-                    e => output.OnError(e),
-                    () => output.OnCompleted()),
+            return Subject.Create<T>(
+                Observer.Create<T>(x => o.SetValue(property, x, priority)),
                 o.GetObservable(property));
-            o.Bind(property, output, priority);
-            return result;
         }
 
         /// <summary>
diff --git a/src/Avalonia.Base/Collections/AvaloniaList.cs b/src/Avalonia.Base/Collections/AvaloniaList.cs
index a3c3015a38..41c2ad6e54 100644
--- a/src/Avalonia.Base/Collections/AvaloniaList.cs
+++ b/src/Avalonia.Base/Collections/AvaloniaList.cs
@@ -350,14 +350,15 @@ namespace Avalonia.Collections
         public void MoveRange(int oldIndex, int count, int newIndex)
         {
             var items = _inner.GetRange(oldIndex, count);
+            var modifiedNewIndex = newIndex;
             _inner.RemoveRange(oldIndex, count);
 
             if (newIndex > oldIndex)
             {
-                newIndex -= count;
+                modifiedNewIndex -= count;
             }
 
-            _inner.InsertRange(newIndex, items);
+            _inner.InsertRange(modifiedNewIndex, items);
 
             if (_collectionChanged != null)
             {
diff --git a/src/Avalonia.Base/Collections/IAvaloniaList.cs b/src/Avalonia.Base/Collections/IAvaloniaList.cs
index 0233cee7a9..48c36976a5 100644
--- a/src/Avalonia.Base/Collections/IAvaloniaList.cs
+++ b/src/Avalonia.Base/Collections/IAvaloniaList.cs
@@ -36,6 +36,21 @@ namespace Avalonia.Collections
         /// <param name="items">The items.</param>
         void InsertRange(int index, IEnumerable<T> items);
 
+        /// <summary>
+        /// Moves an item to a new index.
+        /// </summary>
+        /// <param name="oldIndex">The index of the item to move.</param>
+        /// <param name="newIndex">The index to move the item to.</param>
+        void Move(int oldIndex, int newIndex);
+
+        /// <summary>
+        /// Moves multiple items to a new index.
+        /// </summary>
+        /// <param name="oldIndex">The first index of the items to move.</param>
+        /// <param name="count">The number of items to move.</param>
+        /// <param name="newIndex">The index to move the items to.</param>
+        void MoveRange(int oldIndex, int count, int newIndex);
+
         /// <summary>
         /// Removes multiple items from the collection.
         /// </summary>
diff --git a/src/Avalonia.Base/IAvaloniaObject.cs b/src/Avalonia.Base/IAvaloniaObject.cs
index c11bab2236..c11f8ada7e 100644
--- a/src/Avalonia.Base/IAvaloniaObject.cs
+++ b/src/Avalonia.Base/IAvaloniaObject.cs
@@ -31,6 +31,13 @@ namespace Avalonia
         /// <returns>The value.</returns>
         T GetValue<T>(AvaloniaProperty<T> property);
 
+        /// <summary>
+        /// Checks whether a <see cref="AvaloniaProperty"/> is animating.
+        /// </summary>
+        /// <param name="property">The property.</param>
+        /// <returns>True if the property is animating, otherwise false.</returns>
+        bool IsAnimating(AvaloniaProperty property);
+
         /// <summary>
         /// Checks whether a <see cref="AvaloniaProperty"/> is set on this object.
         /// </summary>
diff --git a/src/Avalonia.Base/PriorityBindingEntry.cs b/src/Avalonia.Base/PriorityBindingEntry.cs
index 63f582a34c..b44b845f25 100644
--- a/src/Avalonia.Base/PriorityBindingEntry.cs
+++ b/src/Avalonia.Base/PriorityBindingEntry.cs
@@ -3,6 +3,7 @@
 
 using System;
 using Avalonia.Data;
+using Avalonia.Threading;
 
 namespace Avalonia
 {
@@ -92,33 +93,50 @@ namespace Avalonia
 
         private void ValueChanged(object value)
         {
-            _owner.Owner.Owner?.VerifyAccess();
-
-            var notification = value as BindingNotification;
-
-            if (notification != null)
+            void Signal()
             {
-                if (notification.HasValue || notification.ErrorType == BindingErrorType.Error)
+                var notification = value as BindingNotification;
+
+                if (notification != null)
                 {
-                    Value = notification.Value;
-                    _owner.Changed(this);
+                    if (notification.HasValue || notification.ErrorType == BindingErrorType.Error)
+                    {
+                        Value = notification.Value;
+                        _owner.Changed(this);
+                    }
+
+                    if (notification.ErrorType != BindingErrorType.None)
+                    {
+                        _owner.Error(this, notification);
+                    }
                 }
-
-                if (notification.ErrorType != BindingErrorType.None)
+                else
                 {
-                    _owner.Error(this, notification);
+                    Value = value;
+                    _owner.Changed(this);
                 }
             }
+
+            if (Dispatcher.UIThread.CheckAccess())
+            {
+                Signal();
+            }
             else
             {
-                Value = value;
-                _owner.Changed(this);
+                Dispatcher.UIThread.InvokeAsync(Signal);
             }
         }
 
         private void Completed()
         {
-            _owner.Completed(this);
+            if (Dispatcher.UIThread.CheckAccess())
+            {
+                _owner.Completed(this);
+            }
+            else
+            {
+                Dispatcher.UIThread.InvokeAsync(() => _owner.Completed(this));
+            }
         }
     }
 }
diff --git a/src/Avalonia.Base/PriorityValue.cs b/src/Avalonia.Base/PriorityValue.cs
index 3726fb7ae5..9b5318083a 100644
--- a/src/Avalonia.Base/PriorityValue.cs
+++ b/src/Avalonia.Base/PriorityValue.cs
@@ -28,8 +28,10 @@ namespace Avalonia
     {
         private readonly Type _valueType;
         private readonly SingleOrDictionary<int, PriorityLevel> _levels = new SingleOrDictionary<int, PriorityLevel>();
-        private object _value;
+
         private readonly Func<object, object> _validate;
+        private static readonly DeferredSetter<PriorityValue, (object value, int priority)> delayedSetter = new DeferredSetter<PriorityValue, (object, int)>();
+        private (object value, int priority) _value;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="PriorityValue"/> class.
@@ -47,11 +49,22 @@ namespace Avalonia
             Owner = owner;
             Property = property;
             _valueType = valueType;
-            _value = AvaloniaProperty.UnsetValue;
-            ValuePriority = int.MaxValue;
+            _value = (AvaloniaProperty.UnsetValue, int.MaxValue);
             _validate = validate;
         }
 
+        /// <summary>
+        /// Gets a value indicating whether the property is animating.
+        /// </summary>
+        public bool IsAnimating
+        {
+            get
+            {
+                return ValuePriority <= (int)BindingPriority.Animation && 
+                    GetLevel(ValuePriority).ActiveBindingIndex != -1;
+            }
+        }
+
         /// <summary>
         /// Gets the owner of the value.
         /// </summary>
@@ -65,16 +78,12 @@ namespace Avalonia
         /// <summary>
         /// Gets the current value.
         /// </summary>
-        public object Value => _value;
+        public object Value => _value.value;
 
         /// <summary>
         /// Gets the priority of the binding that is currently active.
         /// </summary>
-        public int ValuePriority
-        {
-            get;
-            private set;
-        }
+        public int ValuePriority => _value.priority;
 
         /// <summary>
         /// Adds a new binding.
@@ -234,25 +243,36 @@ namespace Avalonia
         /// <param name="priority">The priority level that the value came from.</param>
         private void UpdateValue(object value, int priority)
         {
-            var notification = value as BindingNotification;
+            delayedSetter.SetAndNotify(this,
+                ref _value,
+                UpdateCore,
+                (value, priority));
+        }
+
+        private bool UpdateCore(
+            (object value, int priority) update,
+            ref (object value, int priority) backing,
+            Action<Action> notify)
+        {
+            var val = update.value;
+            var notification = val as BindingNotification;
             object castValue;
 
             if (notification != null)
             {
-                value = (notification.HasValue) ? notification.Value : null;
+                val = (notification.HasValue) ? notification.Value : null;
             }
 
-            if (TypeUtilities.TryConvertImplicit(_valueType, value, out castValue))
+            if (TypeUtilities.TryConvertImplicit(_valueType, val, out castValue))
             {
-                var old = _value;
+                var old = backing.value;
 
                 if (_validate != null && castValue != AvaloniaProperty.UnsetValue)
                 {
                     castValue = _validate(castValue);
                 }
 
-                ValuePriority = priority;
-                _value = castValue;
+                backing = (castValue, update.priority);
 
                 if (notification?.HasValue == true)
                 {
@@ -261,7 +281,7 @@ namespace Avalonia
 
                 if (notification == null || notification.HasValue)
                 {
-                    Owner?.Changed(this, old, _value);
+                    notify(() => Owner?.Changed(this, old, Value));
                 }
 
                 if (notification != null)
@@ -272,14 +292,15 @@ namespace Avalonia
             else
             {
                 Logger.Error(
-                    LogArea.Binding, 
+                    LogArea.Binding,
                     Owner,
                     "Binding produced invalid value for {$Property} ({$PropertyType}): {$Value} ({$ValueType})",
-                    Property.Name, 
-                    _valueType, 
-                    value,
-                    value?.GetType());
+                    Property.Name,
+                    _valueType,
+                    val,
+                    val?.GetType());
             }
+            return true;
         }
     }
 }
diff --git a/src/Avalonia.Base/Reactive/AnonymousSubject`1.cs b/src/Avalonia.Base/Reactive/AnonymousSubject`1.cs
deleted file mode 100644
index c7bed15ecb..0000000000
--- a/src/Avalonia.Base/Reactive/AnonymousSubject`1.cs
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright (c) The Avalonia Project. All rights reserved.
-// Licensed under the MIT license. See licence.md file in the project root for full license information.
-
-using System;
-using System.Reactive.Subjects;
-
-namespace Avalonia.Reactive
-{
-    public class AnonymousSubject<T> : AnonymousSubject<T, T>, ISubject<T>
-    {
-        public AnonymousSubject(IObserver<T> observer, IObservable<T> observable)
-            : base(observer, observable)
-        {
-        }
-    }
-}
diff --git a/src/Avalonia.Base/Reactive/AnonymousSubject`2.cs b/src/Avalonia.Base/Reactive/AnonymousSubject`2.cs
deleted file mode 100644
index 18551d564e..0000000000
--- a/src/Avalonia.Base/Reactive/AnonymousSubject`2.cs
+++ /dev/null
@@ -1,49 +0,0 @@
-// Copyright (c) The Avalonia Project. All rights reserved.
-// Licensed under the MIT license. See licence.md file in the project root for full license information.
-
-using System;
-using System.Reactive.Subjects;
-
-namespace Avalonia.Reactive
-{
-    public class AnonymousSubject<T, U> : ISubject<T, U>
-    {
-        private readonly IObserver<T> _observer;
-        private readonly IObservable<U> _observable;
-
-        public AnonymousSubject(IObserver<T> observer, IObservable<U> observable)
-        {
-            _observer = observer;
-            _observable = observable;
-        }
-
-        public void OnCompleted()
-        {
-            _observer.OnCompleted();
-        }
-
-        public void OnError(Exception error)
-        {
-            if (error == null)
-                throw new ArgumentNullException("error");
-
-            _observer.OnError(error);
-        }
-
-        public void OnNext(T value)
-        {
-            _observer.OnNext(value);
-        }
-
-        public IDisposable Subscribe(IObserver<U> observer)
-        {
-            if (observer == null)
-                throw new ArgumentNullException("observer");
-
-            //
-            // [OK] Use of unsafe Subscribe: non-pretentious wrapping of an observable sequence.
-            //
-            return _observable.Subscribe/*Unsafe*/(observer);
-        }
-    }
-}
diff --git a/src/Avalonia.Base/Utilities/DeferredSetter.cs b/src/Avalonia.Base/Utilities/DeferredSetter.cs
new file mode 100644
index 0000000000..fdfa160134
--- /dev/null
+++ b/src/Avalonia.Base/Utilities/DeferredSetter.cs
@@ -0,0 +1,156 @@
+using System;
+using System.Collections.Generic;
+using System.Reactive.Disposables;
+using System.Runtime.CompilerServices;
+using System.Text;
+
+namespace Avalonia.Utilities
+{
+    /// <summary>
+    /// A utility class to enable deferring assignment until after property-changed notifications are sent.
+    /// </summary>
+    /// <typeparam name="TProperty">The type of the object that represents the property.</typeparam>
+    /// <typeparam name="TSetRecord">The type of value with which to track the delayed assignment.</typeparam>
+    class DeferredSetter<TProperty, TSetRecord>
+        where TProperty: class
+    {
+        private struct NotifyDisposable : IDisposable
+        {
+            private readonly SettingStatus status;
+
+            internal NotifyDisposable(SettingStatus status)
+            {
+                this.status = status;
+                status.Notifying = true;
+            }
+
+            public void Dispose()
+            {
+                status.Notifying = false;
+            }
+        }
+
+        /// <summary>
+        /// Information on current setting/notification status of a property.
+        /// </summary>
+        private class SettingStatus
+        {
+            public bool Notifying { get; set; }
+
+            private Queue<TSetRecord> pendingValues;
+            
+            public Queue<TSetRecord> PendingValues
+            {
+                get
+                {
+                    return pendingValues ?? (pendingValues = new Queue<TSetRecord>());
+                }
+            }
+        }
+
+        private readonly ConditionalWeakTable<TProperty, SettingStatus> setRecords = new ConditionalWeakTable<TProperty, SettingStatus>();
+
+        /// <summary>
+        /// Mark the property as currently notifying.
+        /// </summary>
+        /// <param name="property">The property to mark as notifying.</param>
+        /// <returns>Returns a disposable that when disposed, marks the property as done notifying.</returns>
+        private NotifyDisposable MarkNotifying(TProperty property)
+        {
+            Contract.Requires<InvalidOperationException>(!IsNotifying(property));
+            
+            return new NotifyDisposable(setRecords.GetOrCreateValue(property));
+        }
+
+        /// <summary>
+        /// Check if the property is currently notifying listeners.
+        /// </summary>
+        /// <param name="property">The property.</param>
+        /// <returns>If the property is currently notifying listeners.</returns>
+        private bool IsNotifying(TProperty property)
+            => setRecords.TryGetValue(property, out var value) && value.Notifying;
+
+        /// <summary>
+        /// Add a pending assignment for the property.
+        /// </summary>
+        /// <param name="property">The property.</param>
+        /// <param name="value">The value to assign.</param>
+        private void AddPendingSet(TProperty property, TSetRecord value)
+        {
+            Contract.Requires<InvalidOperationException>(IsNotifying(property));
+
+            setRecords.GetOrCreateValue(property).PendingValues.Enqueue(value);
+        }
+
+        /// <summary>
+        /// Checks if there are any pending assignments for the property.
+        /// </summary>
+        /// <param name="property">The property to check.</param>
+        /// <returns>If the property has any pending assignments.</returns>
+        private bool HasPendingSet(TProperty property)
+        {
+            return setRecords.TryGetValue(property, out var status) && status.PendingValues.Count != 0;
+        }
+
+        /// <summary>
+        /// Gets the first pending assignment for the property.
+        /// </summary>
+        /// <param name="property">The property to check.</param>
+        /// <returns>The first pending assignment for the property.</returns>
+        private TSetRecord GetFirstPendingSet(TProperty property)
+        {
+            return setRecords.GetOrCreateValue(property).PendingValues.Dequeue();
+        }
+
+        public delegate bool SetterDelegate<TValue>(TSetRecord record, ref TValue backing, Action<Action> notifyCallback);
+
+        /// <summary>
+        /// Set the property and notify listeners while ensuring we don't get into a stack overflow as happens with #855 and #824
+        /// </summary>
+        /// <param name="property">The property to set.</param>
+        /// <param name="backing">The backing field for the property</param>
+        /// <param name="setterCallback">
+        /// A callback that actually sets the property.
+        /// The first parameter is the value to set, and the second is a wrapper that takes a callback that sends the property-changed notification.
+        /// </param>
+        /// <param name="value">The value to try to set.</param>
+        public bool SetAndNotify<TValue>(
+            TProperty property,
+            ref TValue backing,
+            SetterDelegate<TValue> setterCallback,
+            TSetRecord value)
+        {
+            Contract.Requires<ArgumentNullException>(setterCallback != null);
+            if (!IsNotifying(property))
+            {
+                bool updated = false;
+                if (!object.Equals(value, backing))
+                {
+                    updated = setterCallback(value, ref backing, notification =>
+                    {
+                        using (MarkNotifying(property))
+                        {
+                            notification();
+                        }
+                    });
+                }
+                while (HasPendingSet(property))
+                {
+                    updated |= setterCallback(GetFirstPendingSet(property), ref backing, notification =>
+                    {
+                        using (MarkNotifying(property))
+                        {
+                            notification();
+                        }
+                    });
+                }
+                return updated;
+            }
+            else if(!object.Equals(value, backing))
+            {
+                AddPendingSet(property, value);
+            }
+            return false;
+        }
+    }
+}
diff --git a/src/Avalonia.Controls/Avalonia.Controls.csproj b/src/Avalonia.Controls/Avalonia.Controls.csproj
index c8f6b4e65a..997e15050f 100644
--- a/src/Avalonia.Controls/Avalonia.Controls.csproj
+++ b/src/Avalonia.Controls/Avalonia.Controls.csproj
@@ -11,7 +11,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Controls.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Controls.xml</DocumentationFile>
     <NoWarn>CS1591;CS0067</NoWarn>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
@@ -21,7 +21,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Controls.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Controls.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
diff --git a/src/Avalonia.Controls/Calendar/Calendar.cs b/src/Avalonia.Controls/Calendar/Calendar.cs
new file mode 100644
index 0000000000..59281c5ad0
--- /dev/null
+++ b/src/Avalonia.Controls/Calendar/Calendar.cs
@@ -0,0 +1,2132 @@
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+
+using Avalonia.Controls.Primitives;
+using Avalonia.Data;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.Media;
+using System;
+using System.Collections.ObjectModel;
+using System.Diagnostics;
+
+namespace Avalonia.Controls
+{
+    /// <summary>
+    /// Specifies values for the different modes of operation of a
+    /// <see cref="T:Avalonia.Controls.Calendar" />.
+    /// </summary>
+    public enum CalendarMode
+    {
+        /// <summary>
+        /// The <see cref="T:Avalonia.Controls.Calendar" /> displays a
+        /// month at a time.
+        /// </summary>
+        Month = 0,
+
+        /// <summary>
+        /// The <see cref="T:Avalonia.Controls.Calendar" /> displays a
+        /// year at a time.
+        /// </summary>
+        Year = 1,
+
+        /// <summary>
+        /// The <see cref="T:Avalonia.Controls.Calendar" /> displays a
+        /// decade at a time.
+        /// </summary>
+        Decade = 2,
+    }
+
+    /// <summary>
+    /// Specifies values that describe the available selection modes for a
+    /// <see cref="T:Avalonia.Controls.Calendar" />.
+    /// </summary>
+    /// <remarks>
+    /// This enumeration provides the values that are used by the SelectionMode
+    /// property.
+    /// </remarks>
+    public enum CalendarSelectionMode
+    {
+        /// <summary>
+        /// Only a single date can be selected. Use the
+        /// <see cref="P:Avalonia.Controls.Calendar.SelectedDate" />
+        /// property to retrieve the selected date.
+        /// </summary>
+        SingleDate = 0,
+
+        /// <summary>
+        /// A single range of dates can be selected. Use 
+        /// <see cref="P:Avalonia.Controls.Calendar.SelectedDates" />
+        /// property to retrieve the selected dates.
+        /// </summary>
+        SingleRange = 1,
+
+        /// <summary>
+        /// Multiple non-contiguous ranges of dates can be selected. Use the
+        /// <see cref="P:Avalonia.Controls.Calendar.SelectedDates" />
+        /// property to retrieve the selected dates.
+        /// </summary>
+        MultipleRange = 2,
+
+        /// <summary>
+        /// No selections are allowed.
+        /// </summary>
+        None = 3,
+    }
+
+    /// <summary>
+    /// Provides data for the
+    /// <see cref="E:Avalonia.Controls.Calendar.DisplayDateChanged" />
+    /// event.
+    /// </summary>
+    public class CalendarDateChangedEventArgs : RoutedEventArgs
+    {
+        /// <summary>
+        /// Gets the date that was previously displayed.
+        /// </summary>
+        /// <value>
+        /// The date previously displayed.
+        /// </value>
+        public DateTime? RemovedDate { get; private set; }
+
+        /// <summary>
+        /// Gets the date to be newly displayed.
+        /// </summary>
+        /// <value>The new date to display.</value>
+        public DateTime? AddedDate { get; private set; }
+
+        /// <summary>
+        /// Initializes a new instance of the CalendarDateChangedEventArgs
+        /// class.
+        /// </summary>
+        /// <param name="removedDate">
+        /// The date that was previously displayed.
+        /// </param>
+        /// <param name="addedDate">The date to be newly displayed.</param>
+        internal CalendarDateChangedEventArgs(DateTime? removedDate, DateTime? addedDate)
+        {
+            RemovedDate = removedDate;
+            AddedDate = addedDate;
+        }
+    }
+
+    /// <summary>
+    /// Provides data for the
+    /// <see cref="E:Avalonia.Controls.Calendar.DisplayModeChanged" />
+    /// event.
+    /// </summary>
+    /// <QualityBand>Mature</QualityBand>
+    public class CalendarModeChangedEventArgs : RoutedEventArgs
+    {
+        /// <summary>
+        /// Gets the previous mode of the
+        /// <see cref="T:Avalonia.Controls.Calendar" />.
+        /// </summary>
+        /// <value>
+        /// A <see cref="T:Avalonia.Controls.CalendarMode" /> representing
+        /// the previous mode.
+        /// </value>
+        public CalendarMode OldMode { get; private set; }
+
+        /// <summary>
+        /// Gets the new mode of the
+        /// <see cref="T:Avalonia.Controls.Calendar" />.
+        /// </summary>
+        /// <value>
+        /// A <see cref="T:Avalonia.Controls.CalendarMode" /> 
+        /// the new mode.
+        /// </value>
+        public CalendarMode NewMode { get; private set; }
+
+        /// <summary>
+        /// Initializes a new instance of the
+        /// <see cref="T:Avalonia.Controls.CalendarModeChangedEventArgs" />
+        /// class.
+        /// </summary>
+        /// <param name="oldMode">The previous mode.</param>
+        /// <param name="newMode">The new mode.</param>
+        public CalendarModeChangedEventArgs(CalendarMode oldMode, CalendarMode newMode)
+        {
+            OldMode = oldMode;
+            NewMode = newMode;
+        }
+    }
+
+    /// <summary>
+    /// Represents a control that enables a user to select a date by using a
+    /// visual calendar display.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// A Calendar control can be used on its own, or as a drop-down part of a
+    /// DatePicker control. For more information, see DatePicker.  A Calendar
+    /// displays either the days of a month, the months of a year, or the years
+    /// of a decade, depending on the value of the DisplayMode property.  When
+    /// displaying the days of a month, the user can select a date, a range of
+    /// dates, or multiple ranges of dates.  The kinds of selections that are
+    /// allowed are controlled by the SelectionMode property.
+    /// </para>
+    /// <para>
+    /// The range of dates displayed is governed by the DisplayDateStart and
+    /// DisplayDateEnd properties.  If DisplayMode is Year or Decade, only
+    /// months or years that contain displayable dates will be displayed.
+    /// Setting the displayable range to a range that does not include the
+    /// current DisplayDate will throw an ArgumentOutOfRangeException.
+    /// </para>
+    /// <para>
+    /// The BlackoutDates property can be used to specify dates that cannot be
+    /// selected. These dates will be displayed as dimmed and disabled.
+    /// </para>
+    /// <para>
+    /// By default, Today is highlighted.  This can be disabled by setting
+    /// IsTodayHighlighted to false.
+    /// </para>
+    /// <para>
+    /// The Calendar control provides basic navigation using either the mouse or
+    /// keyboard. The following table summarizes keyboard navigation.
+    /// 
+    ///     Key Combination     DisplayMode     Action
+    ///     ARROW               Any             Change focused date, unselect
+    ///                                         all selected dates, and select
+    ///                                         new focused date.
+    ///                                         
+    ///     SHIFT+ARROW         Any             If SelectionMode is not set to
+    ///                                         SingleDate or None begin
+    ///                                         selecting a range of dates.
+    ///                                         
+    ///     CTRL+UP ARROW       Any             Switch to the next larger
+    ///                                         DisplayMode.  If DisplayMode is
+    ///                                         already Decade, no action.
+    ///                                         
+    ///     CTRL+DOWN ARROW     Any             Switch to the next smaller
+    ///                                         DisplayMode.  If DisplayMode is
+    ///                                         already Month, no action.
+    ///                                         
+    ///     SPACEBAR            Month           Select focused date.
+    ///     
+    ///     SPACEBAR            Year or Decade  Switch DisplayMode to the Month
+    ///                                         or Year represented by focused
+    ///                                         item.
+    /// </para>
+    /// <para>
+    /// XAML Usage for Classes Derived from Calendar
+    /// If you define a class that derives from Calendar, the class can be used
+    /// as an object element in XAML, and all of the inherited properties and
+    /// events that show a XAML usage in the reference for the Calendar members
+    /// can have the same XAML usage for the derived class. However, the object
+    /// element itself must have a different prefix mapping than the controls:
+    /// mapping shown in the usages, because the derived class comes from an
+    /// assembly and namespace that you create and define.  You must define your
+    /// own prefix mapping to an XML namespace to use the class as an object
+    /// element in XAML.
+    /// </para>
+    /// </remarks>
+    public class Calendar : TemplatedControl
+    {
+        internal const int RowsPerMonth = 7;
+        internal const int ColumnsPerMonth = 7;
+        internal const int RowsPerYear = 3;
+        internal const int ColumnsPerYear = 4;
+
+        private DateTime? _selectedDate;
+        private DateTime _selectedMonth;
+        private DateTime _selectedYear;
+
+        private DateTime _displayDate = DateTime.Today;
+        private DateTime? _displayDateStart = null;
+        private DateTime? _displayDateEnd = null;
+
+        private bool _isShiftPressed;
+        private bool _displayDateIsChanging = false;
+
+        internal CalendarDayButton FocusButton { get; set; }
+        internal CalendarButton FocusCalendarButton { get; set; }
+
+        internal Panel Root { get; set; }
+        internal CalendarItem MonthControl
+        {
+            get
+            {
+
+                if (Root != null && Root.Children.Count > 0)
+                {
+                    return Root.Children[0] as CalendarItem;
+                }
+                return null;
+            }
+        }
+
+        public static readonly StyledProperty<DayOfWeek> FirstDayOfWeekProperty =
+            AvaloniaProperty.Register<Calendar, DayOfWeek>(
+                    nameof(FirstDayOfWeek),
+                    defaultValue: DateTimeHelper.GetCurrentDateFormat().FirstDayOfWeek);
+        /// <summary>
+        /// Gets or sets the day that is considered the beginning of the week.
+        /// </summary>
+        /// <value>
+        /// A <see cref="T:System.DayOfWeek" /> representing the beginning of
+        /// the week. The default is <see cref="F:System.DayOfWeek.Sunday" />.
+        /// </value>
+        public DayOfWeek FirstDayOfWeek
+        {
+            get { return GetValue(FirstDayOfWeekProperty); }
+            set { SetValue(FirstDayOfWeekProperty, value); }
+        }
+        /// <summary>
+        /// FirstDayOfWeekProperty property changed handler.
+        /// </summary>
+        /// <param name="e">The DependencyPropertyChangedEventArgs.</param>
+        private void OnFirstDayOfWeekChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+
+            if (IsValidFirstDayOfWeek(e.NewValue))
+            {
+                UpdateMonths();
+            }
+            else
+            {
+                throw new ArgumentOutOfRangeException("d", "Invalid DayOfWeek");
+            }
+        }
+        /// <summary>
+        /// Inherited code: Requires comment.
+        /// </summary>
+        /// <param name="value">Inherited code: Requires comment 1.</param>
+        /// <returns>Inherited code: Requires comment 2.</returns>
+        private static bool IsValidFirstDayOfWeek(object value)
+        {
+            DayOfWeek day = (DayOfWeek)value;
+
+            return day == DayOfWeek.Sunday
+                || day == DayOfWeek.Monday
+                || day == DayOfWeek.Tuesday
+                || day == DayOfWeek.Wednesday
+                || day == DayOfWeek.Thursday
+                || day == DayOfWeek.Friday
+                || day == DayOfWeek.Saturday;
+        }
+
+        public static readonly StyledProperty<bool> IsTodayHighlightedProperty =
+            AvaloniaProperty.Register<Calendar, bool>(
+                nameof(IsTodayHighlighted),
+                defaultValue: true);
+        /// <summary>
+        /// Gets or sets a value indicating whether the current date is
+        /// highlighted.
+        /// </summary>
+        /// <value>
+        /// True if the current date is highlighted; otherwise, false. The
+        /// default is true.
+        /// </value>
+        public bool IsTodayHighlighted
+        {
+            get { return GetValue(IsTodayHighlightedProperty); }
+            set { SetValue(IsTodayHighlightedProperty, value); }
+        }
+        /// <summary>
+        /// IsTodayHighlightedProperty property changed handler.
+        /// </summary>
+        /// <param name="e">The DependencyPropertyChangedEventArgs.</param>
+        private void OnIsTodayHighlightedChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            if (DisplayDate != null)
+            {
+                int i = DateTimeHelper.CompareYearMonth(DisplayDateInternal, DateTime.Today);
+
+                if (i > -2 && i < 2)
+                {
+                    UpdateMonths();
+                }
+            }
+        }
+
+        public static readonly StyledProperty<IBrush> HeaderBackgroundProperty =
+            AvaloniaProperty.Register<Calendar, IBrush>(nameof(HeaderBackground));
+        public IBrush HeaderBackground
+        {
+            get { return GetValue(HeaderBackgroundProperty); }
+            set { SetValue(HeaderBackgroundProperty, value); }
+        }
+
+        public static readonly StyledProperty<CalendarMode> DisplayModeProperty =
+            AvaloniaProperty.Register<Calendar, CalendarMode>(
+                nameof(DisplayMode),
+                validate: ValidateDisplayMode);
+        /// <summary>
+        /// Gets or sets a value indicating whether the calendar is displayed in
+        /// months, years, or decades.
+        /// </summary>
+        /// <value>
+        /// A value indicating what length of time the
+        /// <see cref="T:System.Windows.Controls.Calendar" /> should display.
+        /// </value>
+        public CalendarMode DisplayMode
+        {
+            get { return GetValue(DisplayModeProperty); }
+            set { SetValue(DisplayModeProperty, value); }
+        }
+        /// <summary>
+        /// DisplayModeProperty property changed handler.
+        /// </summary>
+        /// <param name="e">The DependencyPropertyChangedEventArgs.</param>
+        private void OnDisplayModePropertyChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            CalendarMode mode = (CalendarMode)e.NewValue;
+            CalendarMode oldMode = (CalendarMode)e.OldValue;
+            CalendarItem monthControl = MonthControl;
+
+            if (monthControl != null)
+            {
+                switch (oldMode)
+                {
+                    case CalendarMode.Month:
+                        {
+                            SelectedYear = DisplayDateInternal;
+                            SelectedMonth = DisplayDateInternal;
+                            break;
+                        }
+                    case CalendarMode.Year:
+                        {
+                            DisplayDate = SelectedMonth;
+                            SelectedYear = SelectedMonth;
+                            break;
+                        }
+                    case CalendarMode.Decade:
+                        {
+                            DisplayDate = SelectedYear;
+                            SelectedMonth = SelectedYear;
+                            break;
+                        }
+                }
+
+                switch (mode)
+                {
+                    case CalendarMode.Month:
+                        {
+                            OnMonthClick();
+                            break;
+                        }
+                    case CalendarMode.Year:
+                    case CalendarMode.Decade:
+                        {
+                            OnHeaderClick();
+                            break;
+                        }
+                }
+            }
+            OnDisplayModeChanged(new CalendarModeChangedEventArgs((CalendarMode)e.OldValue, mode));
+        }
+        private static CalendarMode ValidateDisplayMode(Calendar o, CalendarMode mode)
+        {
+            if(IsValidDisplayMode(mode))
+            {
+                return mode;
+            }
+            else
+            {
+                throw new ArgumentOutOfRangeException(nameof(mode), "Invalid DisplayMode");
+            }
+        }
+        private static bool IsValidDisplayMode(CalendarMode mode)
+        {
+            return mode == CalendarMode.Month
+                || mode == CalendarMode.Year
+                || mode == CalendarMode.Decade;
+        }
+        private void OnDisplayModeChanged(CalendarModeChangedEventArgs args)
+        {
+            DisplayModeChanged?.Invoke(this, args);
+        }
+
+        public static readonly StyledProperty<CalendarSelectionMode> SelectionModeProperty =
+            AvaloniaProperty.Register<Calendar, CalendarSelectionMode>(
+                nameof(SelectionMode),
+                defaultValue: CalendarSelectionMode.SingleDate);
+        /// <summary>
+        /// Gets or sets a value that indicates what kind of selections are
+        /// allowed.
+        /// </summary>
+        /// <value>
+        /// A value that indicates the current selection mode. The default is
+        /// <see cref="F:System.Windows.Controls.CalendarSelectionMode.SingleDate" />.
+        /// </value>
+        /// <remarks>
+        /// <para>
+        /// This property determines whether the Calendar allows no selection,
+        /// selection of a single date, or selection of multiple dates.  The
+        /// selection mode is specified with the CalendarSelectionMode
+        /// enumeration.
+        /// </para>
+        /// <para>
+        /// When this property is changed, all selected dates will be cleared.
+        /// </para>
+        /// </remarks>
+        public CalendarSelectionMode SelectionMode
+        {
+            get { return GetValue(SelectionModeProperty); }
+            set { SetValue(SelectionModeProperty, value); }
+        }
+        private void OnSelectionModeChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            if (IsValidSelectionMode(e.NewValue))
+            {
+                _displayDateIsChanging = true;
+                SelectedDate = null;
+                _displayDateIsChanging = false;
+                SelectedDates.Clear();
+            }
+            else
+            {
+                throw new ArgumentOutOfRangeException("d", "Invalid SelectionMode");
+            }
+        }
+        /// <summary>
+        /// Inherited code: Requires comment.
+        /// </summary>
+        /// <param name="value">Inherited code: Requires comment 1.</param>
+        /// <returns>Inherited code: Requires comment 2.</returns>
+        private static bool IsValidSelectionMode(object value)
+        {
+            CalendarSelectionMode mode = (CalendarSelectionMode)value;
+
+            return mode == CalendarSelectionMode.SingleDate
+                || mode == CalendarSelectionMode.SingleRange
+                || mode == CalendarSelectionMode.MultipleRange
+                || mode == CalendarSelectionMode.None;
+        }
+
+        public static readonly DirectProperty<Calendar, DateTime?> SelectedDateProperty =
+            AvaloniaProperty.RegisterDirect<Calendar, DateTime?>(
+                nameof(SelectedDate),
+                o => o.SelectedDate,
+                (o, v) => o.SelectedDate = v,
+                defaultBindingMode: BindingMode.TwoWay);
+        /// <summary>
+        /// Gets or sets the currently selected date.
+        /// </summary>
+        /// <value>The date currently selected. The default is null.</value>
+        /// <exception cref="T:System.ArgumentOutOfRangeException">
+        /// The given date is outside the range specified by
+        /// <see cref="P:System.Windows.Controls.Calendar.DisplayDateStart" />
+        /// and <see cref="P:System.Windows.Controls.Calendar.DisplayDateEnd" />
+        /// -or-
+        /// The given date is in the
+        /// <see cref="P:System.Windows.Controls.Calendar.BlackoutDates" />
+        /// collection.
+        /// </exception>
+        /// <exception cref="T:System.InvalidOperationException">
+        /// If set to anything other than null when
+        /// <see cref="P:System.Windows.Controls.Calendar.SelectionMode" /> is
+        /// set to
+        /// <see cref="F:System.Windows.Controls.CalendarSelectionMode.None" />.
+        /// </exception>
+        /// <remarks>
+        /// Use this property when SelectionMode is set to SingleDate.  In other
+        /// modes, this property will always be the first date in SelectedDates.
+        /// </remarks>
+        public DateTime? SelectedDate
+        {
+            get { return _selectedDate; }
+            set { SetAndRaise(SelectedDateProperty, ref _selectedDate, value); }
+        }
+        private void OnSelectedDateChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            if (!_displayDateIsChanging)
+            {
+                if (SelectionMode != CalendarSelectionMode.None)
+                {
+                    DateTime? addedDate;
+
+                    addedDate = (DateTime?)e.NewValue;
+
+                    if (IsValidDateSelection(this, addedDate))
+                    {
+                        if (addedDate == null)
+                        {
+                            SelectedDates.Clear();
+                        }
+                        else
+                        {
+                            if (!(SelectedDates.Count > 0 && SelectedDates[0] == addedDate.Value))
+                            {
+                                foreach (DateTime item in SelectedDates)
+                                {
+                                    RemovedItems.Add(item);
+                                }
+                                SelectedDates.ClearInternal();
+                                // the value is added as a range so that the
+                                // SelectedDatesChanged event can be thrown with
+                                // all the removed items
+                                SelectedDates.AddRange(addedDate.Value, addedDate.Value);
+                            }
+                        }
+
+                        // We update the LastSelectedDate for only the Single
+                        // mode.  For the other modes it automatically gets
+                        // updated when the HoverEnd is updated.
+                        if (SelectionMode == CalendarSelectionMode.SingleDate)
+                        {
+                            LastSelectedDate = addedDate;
+                        }
+                    }
+                    else
+                    {
+                        throw new ArgumentOutOfRangeException("d", "SelectedDate value is not valid.");
+                    }
+                }
+                else
+                {
+                    throw new InvalidOperationException("The SelectedDate property cannot be set when the selection mode is None.");
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets a collection of selected dates.
+        /// </summary>
+        /// <value>
+        /// A <see cref="T:System.Windows.Controls.SelectedDatesCollection" />
+        /// object that contains the currently selected dates. The default is an
+        /// empty collection.
+        /// </value>
+        /// <remarks>
+        /// Dates can be added to the collection either individually or in a
+        /// range using the AddRange method.  Depending on the value of the
+        /// SelectionMode property, adding a date or range to the collection may
+        /// cause it to be cleared.  The following table lists how
+        /// CalendarSelectionMode affects the SelectedDates property.
+        /// 
+        ///     CalendarSelectionMode   Description
+        ///     None                    No selections are allowed.  SelectedDate
+        ///                             cannot be set and no values can be added
+        ///                             to SelectedDates.
+        ///                             
+        ///     SingleDate              Only a single date can be selected,
+        ///                             either by setting SelectedDate or the
+        ///                             first value in SelectedDates.  AddRange
+        ///                             cannot be used.
+        ///                             
+        ///     SingleRange             A single range of dates can be selected.
+        ///                             Setting SelectedDate, adding a date
+        ///                             individually to SelectedDates, or using
+        ///                             AddRange will clear all previous values
+        ///                             from SelectedDates.
+        ///     MultipleRange           Multiple non-contiguous ranges of dates
+        ///                             can be selected. Adding a date
+        ///                             individually to SelectedDates or using
+        ///                             AddRange will not clear SelectedDates.
+        ///                             Setting SelectedDate will still clear
+        ///                             SelectedDates, but additional dates or
+        ///                             range can then be added.  Adding a range
+        ///                             that includes some dates that are
+        ///                             already selected or overlaps with
+        ///                             another range results in the union of
+        ///                             the ranges and does not cause an
+        ///                             exception.
+        /// </remarks>
+        public SelectedDatesCollection SelectedDates { get; private set; }
+        private static bool IsSelectionChanged(SelectionChangedEventArgs e)
+        {
+            if (e.AddedItems.Count != e.RemovedItems.Count)
+            {
+                return true;
+            }
+            foreach (DateTime addedDate in e.AddedItems)
+            {
+                if (!e.RemovedItems.Contains(addedDate))
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+        internal void OnSelectedDatesCollectionChanged(SelectionChangedEventArgs e)
+        {
+            if (IsSelectionChanged(e))
+            {
+                e.RoutedEvent = SelectingItemsControl.SelectionChangedEvent;
+                e.Source = this;
+                SelectedDatesChanged?.Invoke(this, e);
+            }
+        }
+        
+        internal Collection<DateTime> RemovedItems { get; set; }
+        internal DateTime? LastSelectedDateInternal { get; set; }
+        internal DateTime? LastSelectedDate
+        {
+            get { return LastSelectedDateInternal; }
+            set
+            {
+                LastSelectedDateInternal = value;
+
+                if (SelectionMode == CalendarSelectionMode.None)
+                {
+                    if (FocusButton != null)
+                    {
+                        FocusButton.IsCurrent = false;
+                    }
+                    FocusButton = FindDayButtonFromDay(LastSelectedDate.Value);
+                    if (FocusButton != null)
+                    {
+                        FocusButton.IsCurrent = HasFocusInternal;
+                    }
+                }
+            }
+        }
+
+        internal DateTime SelectedMonth
+        {
+            get { return _selectedMonth; }
+            set
+            {
+                int monthDifferenceStart = DateTimeHelper.CompareYearMonth(value, DisplayDateRangeStart);
+                int monthDifferenceEnd = DateTimeHelper.CompareYearMonth(value, DisplayDateRangeEnd);
+
+                if (monthDifferenceStart >= 0 && monthDifferenceEnd <= 0)
+                {
+                    _selectedMonth = DateTimeHelper.DiscardDayTime(value);
+                }
+                else
+                {
+                    if (monthDifferenceStart < 0)
+                    {
+                        _selectedMonth = DateTimeHelper.DiscardDayTime(DisplayDateRangeStart);
+                    }
+                    else
+                    {
+                        Debug.Assert(monthDifferenceEnd > 0, "monthDifferenceEnd should be greater than 0!");
+                        _selectedMonth = DateTimeHelper.DiscardDayTime(DisplayDateRangeEnd);
+                    }
+                }
+            }
+        }
+        internal DateTime SelectedYear
+        {
+            get { return _selectedYear; }
+            set
+            {
+                if (value.Year < DisplayDateRangeStart.Year)
+                {
+                    _selectedYear = DisplayDateRangeStart;
+                }
+                else
+                {
+                    if (value.Year > DisplayDateRangeEnd.Year)
+                    {
+                        _selectedYear = DisplayDateRangeEnd;
+                    }
+                    else
+                    {
+                        _selectedYear = value;
+                    }
+                }
+            }
+        }
+
+        public static readonly DirectProperty<Calendar, DateTime> DisplayDateProperty =
+            AvaloniaProperty.RegisterDirect<Calendar, DateTime>(
+                nameof(DisplayDate),
+                o => o.DisplayDate,
+                (o, v) => o.DisplayDate = v,
+                defaultBindingMode: BindingMode.TwoWay);
+        /// <summary>
+        /// Gets or sets the date to display.
+        /// </summary>
+        /// <value>The date to display.</value>
+        /// <exception cref="T:System.ArgumentOutOfRangeException">
+        /// The given date is not in the range specified by
+        /// <see cref="P:System.Windows.Controls.Calendar.DisplayDateStart" />
+        /// and
+        /// <see cref="P:System.Windows.Controls.Calendar.DisplayDateEnd" />.
+        /// </exception>
+        /// <remarks>
+        /// <para>
+        /// This property allows the developer to specify a date to display.  If
+        /// this property is a null reference (Nothing in Visual Basic),
+        /// SelectedDate is displayed.  If SelectedDate is also a null reference
+        /// (Nothing in Visual Basic), Today is displayed.  The default is
+        /// Today.
+        /// </para>
+        /// <para>
+        /// To set this property in XAML, use a date specified in the format
+        /// yyyy/mm/dd.  The mm and dd components must always consist of two
+        /// characters, with a leading zero if necessary.  For instance, the
+        /// month of May should be specified as 05.
+        /// </para>
+        /// </remarks>
+        public DateTime DisplayDate
+        {
+            get { return _displayDate; }
+            set { SetAndRaise(DisplayDateProperty, ref _displayDate, value); }
+        }
+        internal DateTime DisplayDateInternal { get; private set; }
+
+        private void OnDisplayDateChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            UpdateDisplayDate(this, (DateTime)e.NewValue, (DateTime)e.OldValue);
+        }
+        private static void UpdateDisplayDate(Calendar c, DateTime addedDate, DateTime removedDate)
+        {
+            Debug.Assert(c != null, "c should not be null!");
+
+            // If DisplayDate < DisplayDateStart, DisplayDate = DisplayDateStart
+            if (DateTime.Compare(addedDate, c.DisplayDateRangeStart) < 0)
+            {
+                c.DisplayDate = c.DisplayDateRangeStart;
+                return;
+            }
+
+            // If DisplayDate > DisplayDateEnd, DisplayDate = DisplayDateEnd
+            if (DateTime.Compare(addedDate, c.DisplayDateRangeEnd) > 0)
+            {
+                c.DisplayDate = c.DisplayDateRangeEnd;
+                return;
+            }
+
+            c.DisplayDateInternal = DateTimeHelper.DiscardDayTime(addedDate);
+            c.UpdateMonths();
+            c.OnDisplayDate(new CalendarDateChangedEventArgs(removedDate, addedDate));
+        }
+        private void OnDisplayDate(CalendarDateChangedEventArgs e)
+        {
+            DisplayDateChanged?.Invoke(this, e);
+        }
+
+        public static readonly DirectProperty<Calendar, DateTime?> DisplayDateStartProperty =
+            AvaloniaProperty.RegisterDirect<Calendar, DateTime?>(
+                nameof(DisplayDateStart),
+                o => o.DisplayDateStart,
+                (o, v) => o.DisplayDateStart = v,
+                defaultBindingMode: BindingMode.TwoWay);
+        /// <summary>
+        /// Gets or sets the first date to be displayed.
+        /// </summary>
+        /// <value>The first date to display.</value>
+        /// <remarks>
+        /// To set this property in XAML, use a date specified in the format
+        /// yyyy/mm/dd.  The mm and dd components must always consist of two
+        /// characters, with a leading zero if necessary.  For instance, the
+        /// month of May should be specified as 05.
+        /// </remarks>
+        public DateTime? DisplayDateStart
+        {
+            get { return _displayDateStart; }
+            set { SetAndRaise(DisplayDateStartProperty, ref _displayDateStart, value); }
+        }
+        private void OnDisplayDateStartChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            if (!_displayDateIsChanging)
+            {
+                DateTime? newValue = e.NewValue as DateTime?;
+
+                if (newValue.HasValue)
+                {
+                    // DisplayDateStart coerces to the value of the
+                    // SelectedDateMin if SelectedDateMin < DisplayDateStart
+                    DateTime? selectedDateMin = SelectedDateMin(this);
+
+                    if (selectedDateMin.HasValue && DateTime.Compare(selectedDateMin.Value, newValue.Value) < 0)
+                    {
+                        DisplayDateStart = selectedDateMin.Value;
+                        return;
+                    }
+
+                    // if DisplayDateStart > DisplayDateEnd,
+                    // DisplayDateEnd = DisplayDateStart
+                    if (DateTime.Compare(newValue.Value, DisplayDateRangeEnd) > 0)
+                    {
+                        DisplayDateEnd = DisplayDateStart;
+                    }
+
+                    // If DisplayDate < DisplayDateStart,
+                    // DisplayDate = DisplayDateStart
+                    if (DateTimeHelper.CompareYearMonth(newValue.Value, DisplayDateInternal) > 0)
+                    {
+                        DisplayDate = newValue.Value;
+                    }
+                }
+                UpdateMonths();
+            }
+        }
+
+        /// <summary>
+        /// Gets a collection of dates that are marked as not selectable.
+        /// </summary>
+        /// <value>
+        /// A collection of dates that cannot be selected. The default value is
+        /// an empty collection.
+        /// </value>
+        /// <exception cref="System.ArgumentOutOfRangeException">
+        /// Adding a date to this collection when it is already selected or
+        /// adding a date outside the range specified by DisplayDateStart and
+        /// DisplayDateEnd.
+        /// </exception>
+        /// <remarks>
+        /// <para>
+        /// Dates in this collection will appear as disabled on the calendar.
+        /// </para>
+        /// <para>
+        /// To make all past dates not selectable, you can use the
+        /// AddDatesInPast method provided by the collection returned by this
+        /// property.
+        /// </para>
+        /// </remarks>
+        public CalendarBlackoutDatesCollection BlackoutDates { get; private set; }
+
+        private static DateTime? SelectedDateMin(Calendar cal)
+        {
+            DateTime selectedDateMin;
+
+            if (cal.SelectedDates.Count > 0)
+            {
+                selectedDateMin = cal.SelectedDates[0];
+                Debug.Assert(DateTime.Compare(cal.SelectedDate.Value, selectedDateMin) == 0, "The SelectedDate should be the minimum selected date!");
+            }
+            else
+            {
+                return null;
+            }
+
+            foreach (DateTime selectedDate in cal.SelectedDates)
+            {
+                if (DateTime.Compare(selectedDate, selectedDateMin) < 0)
+                {
+                    selectedDateMin = selectedDate;
+                }
+            }
+            return selectedDateMin;
+        }
+        internal DateTime DisplayDateRangeStart
+        {
+            get { return DisplayDateStart.GetValueOrDefault(DateTime.MinValue); }
+        }
+
+        public static readonly DirectProperty<Calendar, DateTime?> DisplayDateEndProperty =
+            AvaloniaProperty.RegisterDirect<Calendar, DateTime?>(
+                nameof(DisplayDateEnd),
+                o => o.DisplayDateEnd,
+                (o, v) => o.DisplayDateEnd = v,
+                defaultBindingMode: BindingMode.TwoWay);
+        
+        /// <summary>
+        /// Gets or sets the last date to be displayed.
+        /// </summary>
+        /// <value>The last date to display.</value>
+        /// <remarks>
+        /// To set this property in XAML, use a date specified in the format
+        /// yyyy/mm/dd.  The mm and dd components must always consist of two
+        /// characters, with a leading zero if necessary.  For instance, the
+        /// month of May should be specified as 05.
+        /// </remarks>
+        public DateTime? DisplayDateEnd
+        {
+            get { return _displayDateEnd; }
+            set { SetAndRaise(DisplayDateEndProperty, ref _displayDateEnd, value); }
+        }
+
+        private void OnDisplayDateEndChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            if (!_displayDateIsChanging)
+            {
+                DateTime? newValue = e.NewValue as DateTime?;
+
+                if (newValue.HasValue)
+                {
+                    // DisplayDateEnd coerces to the value of the
+                    // SelectedDateMax if SelectedDateMax > DisplayDateEnd
+                    DateTime? selectedDateMax = SelectedDateMax(this);
+
+                    if (selectedDateMax.HasValue && DateTime.Compare(selectedDateMax.Value, newValue.Value) > 0)
+                    {
+                        DisplayDateEnd = selectedDateMax.Value;
+                        return;
+                    }
+
+                    // if DisplayDateEnd < DisplayDateStart,
+                    // DisplayDateEnd = DisplayDateStart
+                    if (DateTime.Compare(newValue.Value, DisplayDateRangeStart) < 0)
+                    {
+                        DisplayDateEnd = DisplayDateStart;
+                        return;
+                    }
+
+                    // If DisplayDate > DisplayDateEnd,
+                    // DisplayDate = DisplayDateEnd
+                    if (DateTimeHelper.CompareYearMonth(newValue.Value, DisplayDateInternal) < 0)
+                    {
+                        DisplayDate = newValue.Value;
+                    }
+                }
+                UpdateMonths();
+            }
+        }
+
+        private static DateTime? SelectedDateMax(Calendar cal)
+        {
+            DateTime selectedDateMax;
+
+            if (cal.SelectedDates.Count > 0)
+            {
+                selectedDateMax = cal.SelectedDates[0];
+                Debug.Assert(DateTime.Compare(cal.SelectedDate.Value, selectedDateMax) == 0, "The SelectedDate should be the maximum SelectedDate!");
+            }
+            else
+            {
+                return null;
+            }
+
+            foreach (DateTime selectedDate in cal.SelectedDates)
+            {
+                if (DateTime.Compare(selectedDate, selectedDateMax) > 0)
+                {
+                    selectedDateMax = selectedDate;
+                }
+            }
+            return selectedDateMax;
+        }
+        internal DateTime DisplayDateRangeEnd
+        {
+            get { return DisplayDateEnd.GetValueOrDefault(DateTime.MaxValue); }
+        }
+
+        internal DateTime? HoverStart { get; set; }
+        internal int? HoverStartIndex { get; set; }
+        internal DateTime? HoverEndInternal { get; set; }
+        internal DateTime? HoverEnd
+        {
+            get { return HoverEndInternal; }
+            set
+            {
+                HoverEndInternal = value;
+                LastSelectedDate = value;
+            }
+        }
+        internal int? HoverEndIndex { get; set; }
+        internal bool HasFocusInternal { get; set; }
+        internal bool IsMouseSelection { get; set; }
+
+
+        /// <summary>
+        /// Gets or sets a value indicating whether DatePicker should change its 
+        /// DisplayDate because of a SelectedDate change on its Calendar.
+        /// </summary>
+        internal bool DatePickerDisplayDateFlag { get; set; }
+
+        internal CalendarDayButton FindDayButtonFromDay(DateTime day)
+        {
+            CalendarDayButton b;
+            DateTime? d;
+            CalendarItem monthControl = MonthControl;
+
+            // REMOVE_RTM: should be updated if we support MultiCalendar
+            int count = RowsPerMonth * ColumnsPerMonth;
+            if (monthControl != null)
+            {
+                if (monthControl.MonthView != null)
+                {
+                    for (int childIndex = ColumnsPerMonth; childIndex < count; childIndex++)
+                    {
+                        b = monthControl.MonthView.Children[childIndex] as CalendarDayButton;
+                        d = b.DataContext as DateTime?;
+
+                        if (d.HasValue)
+                        {
+                            if (DateTimeHelper.CompareDays(d.Value, day) == 0)
+                            {
+                                return b;
+                            }
+                        }
+                    }
+                }
+            }
+            return null;
+        }
+
+        private void Calendar_SizeChanged(object sender, EventArgs e)
+        {
+            Debug.Assert(sender is Calendar, "The sender should be a Calendar!");
+
+            var size = Bounds.Size;
+            RectangleGeometry rg = new RectangleGeometry();
+            rg.Rect = new Rect(0, 0, size.Width, size.Height);
+
+            if (Root != null)
+            {
+                Root.Clip = rg;
+            }
+        }
+
+        private void OnSelectedMonthChanged(DateTime? selectedMonth)
+        {
+            if (selectedMonth.HasValue)
+            {
+                Debug.Assert(DisplayMode == CalendarMode.Year, "DisplayMode should be Year!");
+                SelectedMonth = selectedMonth.Value;
+                UpdateMonths();
+            }
+        }
+        private void OnSelectedYearChanged(DateTime? selectedYear)
+        {
+            if (selectedYear.HasValue)
+            {
+                Debug.Assert(DisplayMode == CalendarMode.Decade, "DisplayMode should be Decade!");
+                SelectedYear = selectedYear.Value;
+                UpdateMonths();
+            }
+        }
+        internal void OnHeaderClick()
+        {
+            Debug.Assert(DisplayMode == CalendarMode.Year || DisplayMode == CalendarMode.Decade, "The DisplayMode should be Year or Decade");
+            CalendarItem monthControl = MonthControl;
+            if (monthControl != null && monthControl.MonthView != null && monthControl.YearView != null)
+            {
+                monthControl.MonthView.IsVisible = false;
+                monthControl.YearView.IsVisible = true;
+                UpdateMonths();
+            }
+        }
+
+        internal void ResetStates()
+        {
+            CalendarDayButton d;
+            CalendarItem monthControl = MonthControl;
+            int count = RowsPerMonth * ColumnsPerMonth;
+            if (monthControl != null)
+            {
+                if (monthControl.MonthView != null)
+                {
+                    for (int childIndex = ColumnsPerMonth; childIndex < count; childIndex++)
+                    {
+                        d = monthControl.MonthView.Children[childIndex] as CalendarDayButton;
+                        d.IgnoreMouseOverState();
+                    }
+                }
+            }
+
+        }
+
+        internal void UpdateMonths()
+        {
+            CalendarItem monthControl = MonthControl;
+            if (monthControl != null)
+            {
+                switch (DisplayMode)
+                {
+                    case CalendarMode.Month:
+                        {
+                            monthControl.UpdateMonthMode();
+                            break;
+                        }
+                    case CalendarMode.Year:
+                        {
+                            monthControl.UpdateYearMode();
+                            break;
+                        }
+                    case CalendarMode.Decade:
+                        {
+                            monthControl.UpdateDecadeMode();
+                            break;
+                        }
+                }
+            }
+        }
+
+        internal static bool IsValidDateSelection(Calendar cal, DateTime? value)
+        {
+            if (!value.HasValue)
+            {
+                return true;
+            }
+            else
+            {
+                if (cal.BlackoutDates.Contains(value.Value))
+                {
+                    return false;
+                }
+                else
+                {
+                    cal._displayDateIsChanging = true;
+                    if (DateTime.Compare(value.Value, cal.DisplayDateRangeStart) < 0)
+                    {
+                        cal.DisplayDateStart = value;
+                    }
+                    else if (DateTime.Compare(value.Value, cal.DisplayDateRangeEnd) > 0)
+                    {
+                        cal.DisplayDateEnd = value;
+                    }
+                    cal._displayDateIsChanging = false;
+
+                    return true;
+                }
+            }
+        }
+        private static bool IsValidKeyboardSelection(Calendar cal, DateTime? value)
+        {
+            if (!value.HasValue)
+            {
+                return true;
+            }
+            else
+            {
+                if (cal.BlackoutDates.Contains(value.Value))
+                {
+                    return false;
+                }
+                else
+                {
+                    return (DateTime.Compare(value.Value, cal.DisplayDateRangeStart) >= 0 && DateTime.Compare(value.Value, cal.DisplayDateRangeEnd) <= 0);
+                }
+            }
+        }
+
+        /// <summary>
+        /// This method highlights the days in MultiSelection mode without
+        /// adding them to the SelectedDates collection.
+        /// </summary>
+        internal void HighlightDays()
+        {
+            if (HoverEnd != null && HoverStart != null)
+            {
+                int startIndex, endIndex, i;
+                CalendarDayButton b;
+                DateTime? d;
+                CalendarItem monthControl = MonthControl;
+
+                // This assumes a contiguous set of dates:
+                if (HoverEndIndex != null && HoverStartIndex != null)
+                {
+                    SortHoverIndexes(out startIndex, out endIndex);
+
+                    for (i = startIndex; i <= endIndex; i++)
+                    {
+                        b = monthControl.MonthView.Children[i] as CalendarDayButton;
+                        b.IsSelected = true;
+                        d = b.DataContext as DateTime?;
+
+                        if (d.HasValue && DateTimeHelper.CompareDays(HoverEnd.Value, d.Value) == 0)
+                        {
+                            if (FocusButton != null)
+                            {
+                                FocusButton.IsCurrent = false;
+                            }
+                            b.IsCurrent = HasFocusInternal;
+                            FocusButton = b;
+                        }
+                    }
+                }
+            }
+        }
+        /// <summary>
+        /// This method un-highlights the days that were hovered over but not
+        /// added to the SelectedDates collection or un-highlighted the
+        /// previously selected days in SingleRange Mode.
+        /// </summary>
+        internal void UnHighlightDays()
+        {
+            if (HoverEnd != null && HoverStart != null)
+            {
+                CalendarItem monthControl = MonthControl;
+                CalendarDayButton b;
+                DateTime? d;
+
+                if (HoverEndIndex != null && HoverStartIndex != null)
+                {
+                    int i;
+                    SortHoverIndexes(out int startIndex, out int endIndex);
+
+                    if (SelectionMode == CalendarSelectionMode.MultipleRange)
+                    {
+                        for (i = startIndex; i <= endIndex; i++)
+                        {
+                            b = monthControl.MonthView.Children[i] as CalendarDayButton;
+                            d = b.DataContext as DateTime?;
+
+                            if (d.HasValue)
+                            {
+                                if (!SelectedDates.Contains(d.Value))
+                                {
+                                    b.IsSelected = false;
+                                }
+                            }
+                        }
+                    }
+                    else
+                    {
+                        // It is SingleRange
+                        for (i = startIndex; i <= endIndex; i++)
+                        {
+                            (monthControl.MonthView.Children[i] as CalendarDayButton).IsSelected = false;
+                        }
+                    }
+                }
+            }
+        }
+        internal void SortHoverIndexes(out int startIndex, out int endIndex)
+        {
+            if (DateTimeHelper.CompareDays(HoverEnd.Value, HoverStart.Value) > 0)
+            {
+                startIndex = HoverStartIndex.Value;
+                endIndex = HoverEndIndex.Value;
+            }
+            else
+            {
+                startIndex = HoverEndIndex.Value;
+                endIndex = HoverStartIndex.Value;
+            }
+        }
+
+        internal void OnPreviousClick()
+        {
+            if (DisplayMode == CalendarMode.Month && DisplayDate != null)
+            {
+                DateTime? d = DateTimeHelper.AddMonths(DateTimeHelper.DiscardDayTime(DisplayDate), -1);
+                if (d.HasValue)
+                {
+                    if (!LastSelectedDate.HasValue || DateTimeHelper.CompareYearMonth(LastSelectedDate.Value, d.Value) != 0)
+                    {
+                        LastSelectedDate = d.Value;
+                    }
+                    DisplayDate = d.Value;
+                }
+            }
+            else
+            {
+                if (DisplayMode == CalendarMode.Year)
+                {
+                    DateTime? d = DateTimeHelper.AddYears(new DateTime(SelectedMonth.Year, 1, 1), -1);
+
+                    if (d.HasValue)
+                    {
+                        SelectedMonth = d.Value;
+                    }
+                    else
+                    {
+                        SelectedMonth = DateTimeHelper.DiscardDayTime(DisplayDateRangeStart);
+                    }
+                }
+                else
+                {
+                    Debug.Assert(DisplayMode == CalendarMode.Decade, "DisplayMode should be Decade!");
+
+                    DateTime? d = DateTimeHelper.AddYears(new DateTime(SelectedYear.Year, 1, 1), -10);
+
+                    if (d.HasValue)
+                    {
+                        int decade = Math.Max(1, DateTimeHelper.DecadeOfDate(d.Value));
+                        SelectedYear = new DateTime(decade, 1, 1);
+                    }
+                    else
+                    {
+                        SelectedYear = DateTimeHelper.DiscardDayTime(DisplayDateRangeStart);
+                    }
+                }
+                UpdateMonths();
+            }
+        }
+        internal void OnNextClick()
+        {
+            if (DisplayMode == CalendarMode.Month && DisplayDate != null)
+            {
+                DateTime? d = DateTimeHelper.AddMonths(DateTimeHelper.DiscardDayTime(DisplayDate), 1);
+                if (d.HasValue)
+                {
+                    if (!LastSelectedDate.HasValue || DateTimeHelper.CompareYearMonth(LastSelectedDate.Value, d.Value) != 0)
+                    {
+                        LastSelectedDate = d.Value;
+                    }
+                    DisplayDate = d.Value;
+                }
+            }
+            else
+            {
+                if (DisplayMode == CalendarMode.Year)
+                {
+                    DateTime? d = DateTimeHelper.AddYears(new DateTime(SelectedMonth.Year, 1, 1), 1);
+
+                    if (d.HasValue)
+                    {
+                        SelectedMonth = d.Value;
+                    }
+                    else
+                    {
+                        SelectedMonth = DateTimeHelper.DiscardDayTime(DisplayDateRangeEnd);
+                    }
+                }
+                else
+                {
+                    Debug.Assert(DisplayMode == CalendarMode.Decade, "DisplayMode should be Decade");
+
+                    DateTime? d = DateTimeHelper.AddYears(new DateTime(SelectedYear.Year, 1, 1), 10);
+
+                    if (d.HasValue)
+                    {
+                        int decade = Math.Max(1, DateTimeHelper.DecadeOfDate(d.Value));
+                        SelectedYear = new DateTime(decade, 1, 1);
+                    }
+                    else
+                    {
+                        SelectedYear = DateTimeHelper.DiscardDayTime(DisplayDateRangeEnd);
+                    }
+                }
+                UpdateMonths();
+            }
+        }
+
+        /// <summary>
+        /// If the day is a trailing day, Update the DisplayDate.
+        /// </summary>
+        /// <param name="selectedDate">Inherited code: Requires comment.</param>
+        internal void OnDayClick(DateTime selectedDate)
+        {
+            Debug.Assert(DisplayMode == CalendarMode.Month, "DisplayMode should be Month!");
+            int i = DateTimeHelper.CompareYearMonth(selectedDate, DisplayDateInternal);
+
+            if (SelectionMode == CalendarSelectionMode.None)
+            {
+                LastSelectedDate = selectedDate;
+            }
+
+            if (i > 0)
+            {
+                OnNextClick();
+            }
+            else if (i < 0)
+            {
+                OnPreviousClick();
+            }
+        }
+        private void OnMonthClick()
+        {
+            CalendarItem monthControl = MonthControl;
+            if (monthControl != null && monthControl.YearView != null && monthControl.MonthView != null)
+            {
+                monthControl.YearView.IsVisible = false;
+                monthControl.MonthView.IsVisible = true;
+
+                if (!LastSelectedDate.HasValue || DateTimeHelper.CompareYearMonth(LastSelectedDate.Value, DisplayDate) != 0)
+                {
+                    LastSelectedDate = DisplayDate;
+                }
+
+                UpdateMonths();
+            }
+        }
+
+        public override string ToString()
+        {
+            if (SelectedDate != null)
+            {
+                return SelectedDate.Value.ToString(DateTimeHelper.GetCurrentDateFormat());
+            }
+            else
+            {
+                return string.Empty;
+            }
+        }
+
+        public event EventHandler<SelectionChangedEventArgs> SelectedDatesChanged;
+
+        /// <summary>
+        /// Occurs when the
+        /// <see cref="P:System.Windows.Controls.Calendar.DisplayDate" />
+        /// property is changed.
+        /// </summary>
+        /// <remarks>
+        /// This event occurs after DisplayDate is assigned its new value.
+        /// </remarks>
+        public event EventHandler<CalendarDateChangedEventArgs> DisplayDateChanged;
+
+        /// <summary>
+        /// Occurs when the
+        /// <see cref="P:System.Windows.Controls.Calendar.DisplayMode" />
+        /// property is changed.
+        /// </summary>
+        public event EventHandler<CalendarModeChangedEventArgs> DisplayModeChanged;
+
+        /// <summary>
+        /// Inherited code: Requires comment.
+        /// </summary>
+        internal event EventHandler<PointerReleasedEventArgs> DayButtonMouseUp;
+
+        /// <summary>
+        /// This method adds the days that were selected by Keyboard to the
+        /// SelectedDays Collection.
+        /// </summary>
+        private void AddSelection()
+        {
+            if (HoverEnd != null && HoverStart != null)
+            {
+                foreach (DateTime item in SelectedDates)
+                {
+                    RemovedItems.Add(item);
+                }
+
+                SelectedDates.ClearInternal();
+                // In keyboard selection, we are sure that the collection does
+                // not include any blackout days
+                SelectedDates.AddRange(HoverStart.Value, HoverEnd.Value);
+            }
+        }
+        private void ProcessSelection(bool shift, DateTime? lastSelectedDate, int? index)
+        {
+            if (SelectionMode == CalendarSelectionMode.None && lastSelectedDate != null)
+            {
+                OnDayClick(lastSelectedDate.Value);
+                return;
+            }
+            if (lastSelectedDate != null && IsValidKeyboardSelection(this, lastSelectedDate.Value))
+            {
+                if (SelectionMode == CalendarSelectionMode.SingleRange || SelectionMode == CalendarSelectionMode.MultipleRange)
+                {
+                    foreach (DateTime item in SelectedDates)
+                    {
+                        RemovedItems.Add(item);
+                    }
+                    SelectedDates.ClearInternal();
+                    if (shift)
+                    {
+                        CalendarDayButton b;
+                        _isShiftPressed = true;
+                        if (HoverStart == null)
+                        {
+                            if (LastSelectedDate != null)
+                            {
+                                HoverStart = LastSelectedDate;
+                            }
+                            else
+                            {
+                                if (DateTimeHelper.CompareYearMonth(DisplayDateInternal, DateTime.Today) == 0)
+                                {
+                                    HoverStart = DateTime.Today;
+                                }
+                                else
+                                {
+                                    HoverStart = DisplayDateInternal;
+                                }
+                            }
+
+                            b = FindDayButtonFromDay(HoverStart.Value);
+                            if (b != null)
+                            {
+                                HoverStartIndex = b.Index;
+                            }
+                        }
+                        // the index of the SelectedDate is always the last
+                        // selectedDate's index
+                        UnHighlightDays();
+                        // If we hit a BlackOutDay with keyboard we do not
+                        // update the HoverEnd
+                        CalendarDateRange range;
+
+                        if (DateTime.Compare(HoverStart.Value, lastSelectedDate.Value) < 0)
+                        {
+                            range = new CalendarDateRange(HoverStart.Value, lastSelectedDate.Value);
+                        }
+                        else
+                        {
+                            range = new CalendarDateRange(lastSelectedDate.Value, HoverStart.Value);
+                        }
+
+                        if (!BlackoutDates.ContainsAny(range))
+                        {
+                            HoverEnd = lastSelectedDate;
+
+                            if (index.HasValue)
+                            {
+                                HoverEndIndex += index;
+                            }
+                            else
+                            {
+                                // For Home, End, PageUp and PageDown Keys there
+                                // is no easy way to predict the index value
+                                b = FindDayButtonFromDay(HoverEndInternal.Value);
+
+                                if (b != null)
+                                {
+                                    HoverEndIndex = b.Index;
+                                }
+                            }
+                        }
+
+                        OnDayClick(HoverEnd.Value);
+                        HighlightDays();
+                    }
+                    else
+                    {
+                        HoverStart = lastSelectedDate;
+                        HoverEnd = lastSelectedDate;
+                        AddSelection();
+                        OnDayClick(lastSelectedDate.Value);
+                    }
+                }
+                else
+                {
+                    // ON CLEAR 
+                    LastSelectedDate = lastSelectedDate.Value;
+                    if (SelectedDates.Count > 0)
+                    {
+                        SelectedDates[0] = lastSelectedDate.Value;
+                    }
+                    else
+                    {
+                        SelectedDates.Add(lastSelectedDate.Value);
+                    }
+                    OnDayClick(lastSelectedDate.Value);
+                }
+            }
+        }
+
+        protected override void OnPointerReleased(PointerReleasedEventArgs e)
+        {
+            base.OnPointerReleased(e);
+            if (!HasFocusInternal && e.MouseButton == MouseButton.Left)
+            {
+                FocusManager.Instance.Focus(this);
+            }
+        }
+
+        internal void OnDayButtonMouseUp(PointerReleasedEventArgs e)
+        {
+            DayButtonMouseUp?.Invoke(this, e);
+        }
+
+        /// <summary>
+        /// Default mouse wheel handler for the calendar control.
+        /// </summary>
+        /// <param name="e">Mouse wheel event args.</param>
+        protected override void OnPointerWheelChanged(PointerWheelEventArgs e)
+        {
+            base.OnPointerWheelChanged(e);
+            if (!e.Handled)
+            {
+                CalendarExtensions.GetMetaKeyState(e.InputModifiers, out bool ctrl, out bool shift);
+
+                if (!ctrl)
+                {
+                    if (e.Delta.Y > 0)
+                    {
+                        ProcessPageUpKey(false);
+                    }
+                    else
+                    {
+                        ProcessPageDownKey(false);
+                    }
+                }
+                else
+                {
+                    if (e.Delta.Y > 0)
+                    {
+                        ProcessDownKey(ctrl, shift);
+                    }
+                    else
+                    {
+                        ProcessUpKey(ctrl, shift);
+                    }
+                }
+                e.Handled = true;
+            }
+        }
+        internal void Calendar_KeyDown(object sender, KeyEventArgs e)
+        {
+            Calendar c = sender as Calendar;
+            Debug.Assert(c != null, "c should not be null!");
+
+            if (!e.Handled && c.IsEnabled)
+            {
+                e.Handled = ProcessCalendarKey(e);
+            }
+        }
+        internal bool ProcessCalendarKey(KeyEventArgs e)
+        {
+            if (DisplayMode == CalendarMode.Month)
+            {
+                if (LastSelectedDate.HasValue && DisplayDateInternal != null)
+                {
+                    // If a blackout day is inactive, when clicked on it, the
+                    // previous inactive day which is not a blackout day can get
+                    // the focus.  In this case we should allow keyboard
+                    // functions on that inactive day
+                    if (DateTimeHelper.CompareYearMonth(LastSelectedDate.Value, DisplayDateInternal) != 0 && FocusButton != null && !FocusButton.IsInactive)
+                    {
+                        return true;
+                    }
+                }
+            }
+
+            // Some keys (e.g. Left/Right) need to be translated in RightToLeft mode
+            Key invariantKey = e.Key;  //InteractionHelper.GetLogicalKey(FlowDirection, e.Key);
+
+            CalendarExtensions.GetMetaKeyState(e.Modifiers, out bool ctrl, out bool shift);
+
+            switch (invariantKey)
+            {
+                case Key.Up:
+                    {
+                        ProcessUpKey(ctrl, shift);
+                        return true;
+                    }
+                case Key.Down:
+                    {
+                        ProcessDownKey(ctrl, shift);
+                        return true;
+                    }
+                case Key.Left:
+                    {
+                        ProcessLeftKey(shift);
+                        return true;
+                    }
+                case Key.Right:
+                    {
+                        ProcessRightKey(shift);
+                        return true;
+                    }
+                case Key.PageDown:
+                    {
+                        ProcessPageDownKey(shift);
+                        return true;
+                    }
+                case Key.PageUp:
+                    {
+                        ProcessPageUpKey(shift);
+                        return true;
+                    }
+                case Key.Home:
+                    {
+                        ProcessHomeKey(shift);
+                        return true;
+                    }
+                case Key.End:
+                    {
+                        ProcessEndKey(shift);
+                        return true;
+                    }
+                case Key.Enter:
+                case Key.Space:
+                    {
+                        return ProcessEnterKey();
+                    }
+            }
+            return false;
+        }
+        internal void ProcessUpKey(bool ctrl, bool shift)
+        {
+            switch (DisplayMode)
+            {
+                case CalendarMode.Month:
+                    {
+                        if (ctrl)
+                        {
+                            SelectedMonth = DisplayDateInternal;
+                            DisplayMode = CalendarMode.Year;
+                        }
+                        else
+                        {
+                            DateTime? selectedDate = DateTimeHelper.AddDays(LastSelectedDate.GetValueOrDefault(DateTime.Today), -ColumnsPerMonth);
+                            ProcessSelection(shift, selectedDate, -ColumnsPerMonth);
+                        }
+                        break;
+                    }
+                case CalendarMode.Year:
+                    {
+                        if (ctrl)
+                        {
+                            SelectedYear = SelectedMonth;
+                            DisplayMode = CalendarMode.Decade;
+                        }
+                        else
+                        {
+                            DateTime? selectedMonth = DateTimeHelper.AddMonths(_selectedMonth, -ColumnsPerYear);
+                            OnSelectedMonthChanged(selectedMonth);
+                        }
+                        break;
+                    }
+                case CalendarMode.Decade:
+                    {
+                        if (!ctrl)
+                        {
+                            DateTime? selectedYear = DateTimeHelper.AddYears(SelectedYear, -ColumnsPerYear);
+                            OnSelectedYearChanged(selectedYear);
+                        }
+                        break;
+                    }
+            }
+        }
+        internal void ProcessDownKey(bool ctrl, bool shift)
+        {
+            switch (DisplayMode)
+            {
+                case CalendarMode.Month:
+                    {
+                        if (!ctrl || shift)
+                        {
+                            DateTime? selectedDate = DateTimeHelper.AddDays(LastSelectedDate.GetValueOrDefault(DateTime.Today), ColumnsPerMonth);
+                            ProcessSelection(shift, selectedDate, ColumnsPerMonth);
+                        }
+                        break;
+                    }
+                case CalendarMode.Year:
+                    {
+                        if (ctrl)
+                        {
+                            DisplayDate = SelectedMonth;
+                            DisplayMode = CalendarMode.Month;
+                        }
+                        else
+                        {
+                            DateTime? selectedMonth = DateTimeHelper.AddMonths(_selectedMonth, ColumnsPerYear);
+                            OnSelectedMonthChanged(selectedMonth);
+                        }
+                        break;
+                    }
+                case CalendarMode.Decade:
+                    {
+                        if (ctrl)
+                        {
+                            SelectedMonth = SelectedYear;
+                            DisplayMode = CalendarMode.Year;
+                        }
+                        else
+                        {
+                            DateTime? selectedYear = DateTimeHelper.AddYears(SelectedYear, ColumnsPerYear);
+                            OnSelectedYearChanged(selectedYear);
+                        }
+                        break;
+                    }
+            }
+        }
+        internal void ProcessLeftKey(bool shift)
+        {
+            switch (DisplayMode)
+            {
+                case CalendarMode.Month:
+                    {
+                        DateTime? selectedDate = DateTimeHelper.AddDays(LastSelectedDate.GetValueOrDefault(DateTime.Today), -1);
+                        ProcessSelection(shift, selectedDate, -1);
+                        break;
+                    }
+                case CalendarMode.Year:
+                    {
+                        DateTime? selectedMonth = DateTimeHelper.AddMonths(_selectedMonth, -1);
+                        OnSelectedMonthChanged(selectedMonth);
+                        break;
+                    }
+                case CalendarMode.Decade:
+                    {
+                        DateTime? selectedYear = DateTimeHelper.AddYears(SelectedYear, -1);
+                        OnSelectedYearChanged(selectedYear);
+                        break;
+                    }
+            }
+        }
+        internal void ProcessRightKey(bool shift)
+        {
+            switch (DisplayMode)
+            {
+                case CalendarMode.Month:
+                    {
+                        DateTime? selectedDate = DateTimeHelper.AddDays(LastSelectedDate.GetValueOrDefault(DateTime.Today), 1);
+                        ProcessSelection(shift, selectedDate, 1);
+                        break;
+                    }
+                case CalendarMode.Year:
+                    {
+                        DateTime? selectedMonth = DateTimeHelper.AddMonths(_selectedMonth, 1);
+                        OnSelectedMonthChanged(selectedMonth);
+                        break;
+                    }
+                case CalendarMode.Decade:
+                    {
+                        DateTime? selectedYear = DateTimeHelper.AddYears(SelectedYear, 1);
+                        OnSelectedYearChanged(selectedYear);
+                        break;
+                    }
+            }
+        }
+        private bool ProcessEnterKey()
+        {
+            switch (DisplayMode)
+            {
+                case CalendarMode.Year:
+                    {
+                        DisplayDate = SelectedMonth;
+                        DisplayMode = CalendarMode.Month;
+                        return true;
+                    }
+                case CalendarMode.Decade:
+                    {
+                        SelectedMonth = SelectedYear;
+                        DisplayMode = CalendarMode.Year;
+                        return true;
+                    }
+            }
+            return false;
+        }
+        internal void ProcessHomeKey(bool shift)
+        {
+            switch (DisplayMode)
+            {
+                case CalendarMode.Month:
+                    {
+                        // REMOVE_RTM: Not all types of calendars start with Day1. If Non-Gregorian is supported check this:
+                        DateTime? selectedDate = new DateTime(DisplayDateInternal.Year, DisplayDateInternal.Month, 1);
+                        ProcessSelection(shift, selectedDate, null);
+                        break;
+                    }
+                case CalendarMode.Year:
+                    {
+                        DateTime selectedMonth = new DateTime(_selectedMonth.Year, 1, 1);
+                        OnSelectedMonthChanged(selectedMonth);
+                        break;
+                    }
+                case CalendarMode.Decade:
+                    {
+                        DateTime? selectedYear = new DateTime(DateTimeHelper.DecadeOfDate(SelectedYear), 1, 1);
+                        OnSelectedYearChanged(selectedYear);
+                        break;
+                    }
+            }
+        }
+        internal void ProcessEndKey(bool shift)
+        {
+            switch (DisplayMode)
+            {
+                case CalendarMode.Month:
+                    {
+                        if (DisplayDate != null)
+                        {
+                            DateTime? selectedDate = new DateTime(DisplayDateInternal.Year, DisplayDateInternal.Month, 1);
+
+                            if (DateTimeHelper.CompareYearMonth(DateTime.MaxValue, selectedDate.Value) > 0)
+                            {
+                                // since DisplayDate is not equal to
+                                // DateTime.MaxValue we are sure selectedDate is\
+                                // not null
+                                selectedDate = DateTimeHelper.AddMonths(selectedDate.Value, 1).Value;
+                                selectedDate = DateTimeHelper.AddDays(selectedDate.Value, -1).Value;
+                            }
+                            else
+                            {
+                                selectedDate = DateTime.MaxValue;
+                            }
+                            ProcessSelection(shift, selectedDate, null);
+                        }
+                        break;
+                    }
+                case CalendarMode.Year:
+                    {
+                        DateTime selectedMonth = new DateTime(_selectedMonth.Year, 12, 1);
+                        OnSelectedMonthChanged(selectedMonth);
+                        break;
+                    }
+                case CalendarMode.Decade:
+                    {
+                        DateTime? selectedYear = new DateTime(DateTimeHelper.EndOfDecade(SelectedYear), 1, 1);
+                        OnSelectedYearChanged(selectedYear);
+                        break;
+                    }
+            }
+        }
+        internal void ProcessPageDownKey(bool shift)
+        {
+            switch (DisplayMode)
+            {
+                case CalendarMode.Month:
+                    {
+                        DateTime? selectedDate = DateTimeHelper.AddMonths(LastSelectedDate.GetValueOrDefault(DateTime.Today), 1);
+                        ProcessSelection(shift, selectedDate, null);
+                        break;
+                    }
+                case CalendarMode.Year:
+                    {
+                        DateTime? selectedMonth = DateTimeHelper.AddYears(_selectedMonth, 1);
+                        OnSelectedMonthChanged(selectedMonth);
+                        break;
+                    }
+                case CalendarMode.Decade:
+                    {
+                        DateTime? selectedYear = DateTimeHelper.AddYears(SelectedYear, 10);
+                        OnSelectedYearChanged(selectedYear);
+                        break;
+                    }
+            }
+        }
+        internal void ProcessPageUpKey(bool shift)
+        {
+            switch (DisplayMode)
+            {
+                case CalendarMode.Month:
+                    {
+                        DateTime? selectedDate = DateTimeHelper.AddMonths(LastSelectedDate.GetValueOrDefault(DateTime.Today), -1);
+                        ProcessSelection(shift, selectedDate, null);
+                        break;
+                    }
+                case CalendarMode.Year:
+                    {
+                        DateTime? selectedMonth = DateTimeHelper.AddYears(_selectedMonth, -1);
+                        OnSelectedMonthChanged(selectedMonth);
+                        break;
+                    }
+                case CalendarMode.Decade:
+                    {
+                        DateTime? selectedYear = DateTimeHelper.AddYears(SelectedYear, -10);
+                        OnSelectedYearChanged(selectedYear);
+                        break;
+                    }
+            }
+        }
+        private void Calendar_KeyUp(object sender, KeyEventArgs e)
+        {
+            if (!e.Handled && (e.Key == Key.LeftShift || e.Key == Key.RightShift))
+            {
+                ProcessShiftKeyUp();
+            }
+        }
+        internal void ProcessShiftKeyUp()
+        {
+            if (_isShiftPressed && (SelectionMode == CalendarSelectionMode.SingleRange || SelectionMode == CalendarSelectionMode.MultipleRange))
+            {
+                AddSelection();
+                _isShiftPressed = false;
+            }
+        }
+
+        protected override void OnGotFocus(GotFocusEventArgs e)
+        {
+            base.OnGotFocus(e);
+            HasFocusInternal = true;
+
+            switch (DisplayMode)
+            {
+                case CalendarMode.Month:
+                    {
+                        DateTime focusDate;
+                        if (LastSelectedDate.HasValue && DateTimeHelper.CompareYearMonth(DisplayDateInternal, LastSelectedDate.Value) == 0)
+                        {
+                            focusDate = LastSelectedDate.Value;
+                        }
+                        else
+                        {
+                            focusDate = DisplayDate;
+                            LastSelectedDate = DisplayDate;
+                        }
+                        Debug.Assert(focusDate != null, "focusDate should not be null!");
+                        FocusButton = FindDayButtonFromDay(focusDate);
+
+                        if (FocusButton != null)
+                        {
+                            FocusButton.IsCurrent = true;
+                        }
+                        break;
+                    }
+                case CalendarMode.Year:
+                case CalendarMode.Decade:
+                    {
+                        if (this.FocusCalendarButton != null)
+                        {
+                            FocusCalendarButton.IsCalendarButtonFocused = true;
+                        }
+                        break;
+                    }
+            }
+        }
+        protected override void OnLostFocus(RoutedEventArgs e)
+        {
+            base.OnLostFocus(e);
+            HasFocusInternal = false;
+
+            switch (DisplayMode)
+            {
+                case CalendarMode.Month:
+                    {
+                        if (FocusButton != null)
+                        {
+                            FocusButton.IsCurrent = false;
+                        }
+                        break;
+                    }
+                case CalendarMode.Year:
+                case CalendarMode.Decade:
+                    {
+                        if (FocusCalendarButton != null)
+                        {
+                            FocusCalendarButton.IsCalendarButtonFocused = false;
+                        }
+                        break;
+                    }
+            }
+        }
+        /// <summary>
+        ///  Called when the IsEnabled property changes.
+        /// </summary>
+        /// <param name="e">Property changed args.</param>
+        private void OnIsEnabledChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            Debug.Assert(e.NewValue is bool, "NewValue should be a boolean!");
+            bool isEnabled = (bool)e.NewValue;
+
+            if (MonthControl != null)
+            {
+                MonthControl.UpdateDisabled(isEnabled);
+            }
+        }
+
+        static Calendar()
+        {
+            IsEnabledProperty.Changed.AddClassHandler<Calendar>(x => x.OnIsEnabledChanged);
+            FirstDayOfWeekProperty.Changed.AddClassHandler<Calendar>(x => x.OnFirstDayOfWeekChanged);
+            IsTodayHighlightedProperty.Changed.AddClassHandler<Calendar>(x => x.OnIsTodayHighlightedChanged);
+            DisplayModeProperty.Changed.AddClassHandler<Calendar>(x => x.OnDisplayModePropertyChanged);
+            SelectionModeProperty.Changed.AddClassHandler<Calendar>(x => x.OnSelectionModeChanged);
+            SelectedDateProperty.Changed.AddClassHandler<Calendar>(x => x.OnSelectedDateChanged);
+            DisplayDateProperty.Changed.AddClassHandler<Calendar>(x => x.OnDisplayDateChanged);
+            DisplayDateStartProperty.Changed.AddClassHandler<Calendar>(x => x.OnDisplayDateStartChanged);
+            DisplayDateEndProperty.Changed.AddClassHandler<Calendar>(x => x.OnDisplayDateEndChanged);
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the
+        /// <see cref="T:System.Windows.Controls.Calendar" /> class.
+        /// </summary>
+        public Calendar()
+        {
+            UpdateDisplayDate(this, this.DisplayDate, DateTime.MinValue);
+            BlackoutDates = new CalendarBlackoutDatesCollection(this);
+            SelectedDates = new SelectedDatesCollection(this);
+            RemovedItems = new Collection<DateTime>();
+        }
+
+        private const string PART_ElementRoot = "Root";
+        private const string PART_ElementMonth = "CalendarItem";
+        /// <summary>
+        /// Builds the visual tree for the
+        /// <see cref="T:System.Windows.Controls.Calendar" /> when a new
+        /// template is applied.
+        /// </summary>
+        protected override void OnTemplateApplied(TemplateAppliedEventArgs e)
+        {
+            base.OnTemplateApplied(e);
+
+            Root = e.NameScope.Find<Panel>(PART_ElementRoot);
+
+            SelectedMonth = DisplayDate;
+            SelectedYear = DisplayDate;
+
+            if (Root != null)
+            {
+                CalendarItem month = e.NameScope.Find<CalendarItem>(PART_ElementMonth);
+
+                if (month != null)
+                {
+                    month.Owner = this;
+                }
+            }
+
+            LayoutUpdated += Calendar_SizeChanged;
+            KeyDown += Calendar_KeyDown;
+            KeyUp += Calendar_KeyUp;
+        }
+
+    }
+}
diff --git a/src/Avalonia.Controls/Calendar/CalendarBlackoutDatesCollection.cs b/src/Avalonia.Controls/Calendar/CalendarBlackoutDatesCollection.cs
new file mode 100644
index 0000000000..0d48418683
--- /dev/null
+++ b/src/Avalonia.Controls/Calendar/CalendarBlackoutDatesCollection.cs
@@ -0,0 +1,215 @@
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+
+using Avalonia.Threading;
+using System;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Threading;
+
+namespace Avalonia.Controls.Primitives
+{
+    public sealed class CalendarBlackoutDatesCollection : ObservableCollection<CalendarDateRange>
+    {
+        /// <summary>
+        /// The Calendar whose dates this object represents.
+        /// </summary>
+        private Calendar _owner;
+        
+        /// <summary>
+        /// Initializes a new instance of the
+        /// <see cref="T:Avalonia.Controls.Primitives.CalendarBlackoutDatesCollection" />
+        /// class.
+        /// </summary>
+        /// <param name="owner">
+        /// The <see cref="T:Avalonia.Controls.Calendar" /> whose dates
+        /// this object represents.
+        /// </param>
+        public CalendarBlackoutDatesCollection(Calendar owner)
+        {
+            _owner = owner ?? throw new ArgumentNullException(nameof(owner));
+        }
+
+        /// <summary>
+        /// Adds all dates before <see cref="P:System.DateTime.Today" /> to the
+        /// collection.
+        /// </summary>
+        public void AddDatesInPast()
+        {
+            Add(new CalendarDateRange(DateTime.MinValue, DateTime.Today.AddDays(-1)));
+        }
+
+        /// <summary>
+        /// Returns a value that represents whether this collection contains the
+        /// specified date.
+        /// </summary>
+        /// <param name="date">The date to search for.</param>
+        /// <returns>
+        /// True if the collection contains the specified date; otherwise,
+        /// false.
+        /// </returns>
+        public bool Contains(DateTime date)
+        {
+            int count = Count;
+            for (int i = 0; i < count; i++)
+            {
+                if (DateTimeHelper.InRange(date, this[i]))
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        /// <summary>
+        /// Returns a value that represents whether this collection contains the
+        /// specified range of dates.
+        /// </summary>
+        /// <param name="start">The start of the date range.</param>
+        /// <param name="end">The end of the date range.</param>
+        /// <returns>
+        /// True if all dates in the range are contained in the collection;
+        /// otherwise, false.
+        /// </returns>
+        public bool Contains(DateTime start, DateTime end)
+        {
+            DateTime rangeStart;
+            DateTime rangeEnd;
+
+            if (DateTime.Compare(end, start) > -1)
+            {
+                rangeStart = DateTimeHelper.DiscardTime(start).Value;
+                rangeEnd = DateTimeHelper.DiscardTime(end).Value;
+            }
+            else
+            {
+                rangeStart = DateTimeHelper.DiscardTime(end).Value;
+                rangeEnd = DateTimeHelper.DiscardTime(start).Value;
+            }
+
+            int count = Count;
+            for (int i = 0; i < count; i++)
+            {
+                CalendarDateRange range = this[i];
+                if (DateTime.Compare(range.Start, rangeStart) == 0 && DateTime.Compare(range.End, rangeEnd) == 0)
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        /// <summary>
+        /// Returns a value that represents whether this collection contains any
+        /// date in the specified range.
+        /// </summary>
+        /// <param name="range">The range of dates to search for.</param>
+        /// <returns>
+        /// True if any date in the range is contained in the collection;
+        /// otherwise, false.
+        /// </returns>
+        public bool ContainsAny(CalendarDateRange range)
+        {
+            return this.Any(r => r.ContainsAny(range));
+        }
+
+        /// <summary>
+        /// Removes all items from the collection.
+        /// </summary>
+        /// <remarks>
+        /// This implementation raises the CollectionChanged event.
+        /// </remarks>
+        protected override void ClearItems()
+        {
+            EnsureValidThread();
+
+            base.ClearItems();
+            _owner.UpdateMonths();
+        }
+
+        /// <summary>
+        /// Inserts an item into the collection at the specified index.
+        /// </summary>
+        /// <param name="index">
+        /// The zero-based index at which item should be inserted.
+        /// </param>
+        /// <param name="item">The object to insert.</param>
+        /// <remarks>
+        /// This implementation raises the CollectionChanged event.
+        /// </remarks>
+        protected override void InsertItem(int index, CalendarDateRange item)
+        {
+            EnsureValidThread();
+
+            if (!IsValid(item))
+            {
+                throw new ArgumentOutOfRangeException("Value is not valid.");
+            }
+
+            base.InsertItem(index, item);
+            _owner.UpdateMonths();
+        }
+
+        /// <summary>
+        /// Removes the item at the specified index of the collection.
+        /// </summary>
+        /// <param name="index">
+        /// The zero-based index of the element to remove.
+        /// </param>
+        /// <remarks>
+        /// This implementation raises the CollectionChanged event.
+        /// </remarks>
+        protected override void RemoveItem(int index)
+        {
+            EnsureValidThread();
+
+            base.RemoveItem(index);
+            _owner.UpdateMonths();
+        }
+
+        /// <summary>
+        /// Replaces the element at the specified index.
+        /// </summary>
+        /// <param name="index">
+        /// The zero-based index of the element to replace.
+        /// </param>
+        /// <param name="item">
+        /// The new value for the element at the specified index.
+        /// </param>
+        /// <remarks>
+        /// This implementation raises the CollectionChanged event.
+        /// </remarks>
+        protected override void SetItem(int index, CalendarDateRange item)
+        {
+            EnsureValidThread();
+
+            if (!IsValid(item))
+            {
+                throw new ArgumentOutOfRangeException("Value is not valid.");
+            }
+
+            base.SetItem(index, item);
+            _owner.UpdateMonths();
+        }
+        
+        private bool IsValid(CalendarDateRange item)
+        {
+            foreach (DateTime day in _owner.SelectedDates)
+            {
+                if (DateTimeHelper.InRange(day, item))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+        
+        private void EnsureValidThread()
+        {
+            Dispatcher.UIThread.VerifyAccess();
+        }
+    }
+}
diff --git a/src/Avalonia.Controls/Calendar/CalendarButton.cs b/src/Avalonia.Controls/Calendar/CalendarButton.cs
new file mode 100644
index 0000000000..224d9b782b
--- /dev/null
+++ b/src/Avalonia.Controls/Calendar/CalendarButton.cs
@@ -0,0 +1,193 @@
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+
+using Avalonia.Input;
+using System;
+
+namespace Avalonia.Controls.Primitives
+{
+    /// <summary>
+    /// Represents a button on a
+    /// <see cref="T:Avalonia.Controls.Calendar" />.
+    /// </summary>
+    public sealed class CalendarButton : Button
+    {
+        /// <summary>
+        /// A value indicating whether the button is focused.
+        /// </summary>
+        private bool _isCalendarButtonFocused;
+
+        /// <summary>
+        /// A value indicating whether the button is inactive.
+        /// </summary>
+        private bool _isInactive;
+
+        /// <summary>
+        /// A value indicating whether the button is selected.
+        /// </summary>
+        private bool _isSelected;
+
+        /// <summary>
+        /// Initializes a new instance of the
+        /// <see cref="T:Avalonia.Controls.Primitives.CalendarButton" />
+        /// class.
+        /// </summary>
+        public CalendarButton()
+            : base()
+        {
+            Content = DateTimeHelper.GetCurrentDateFormat().AbbreviatedMonthNames[0];
+        }
+
+        /// <summary>
+        /// Gets or sets the Calendar associated with this button.
+        /// </summary>
+        internal Calendar Owner { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the button is focused.
+        /// </summary>
+        internal bool IsCalendarButtonFocused
+        {
+            get { return _isCalendarButtonFocused; }
+            set
+            {
+                if (_isCalendarButtonFocused != value)
+                {
+                    _isCalendarButtonFocused = value;
+                    SetPseudoClasses();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the button is inactive.
+        /// </summary>
+        internal bool IsInactive
+        {
+            get { return _isInactive; }
+            set
+            {
+                if (_isInactive != value)
+                {
+                    _isInactive = value;
+                    SetPseudoClasses();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the button is selected.
+        /// </summary>
+        internal bool IsSelected
+        {
+            get { return _isSelected; }
+            set
+            {
+                if (_isSelected != value)
+                {
+                    _isSelected = value;
+                    SetPseudoClasses();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Builds the visual tree for the
+        /// <see cref="T:System.Windows.Controls.Primitives.CalendarButton" />
+        /// when a new template is applied.
+        /// </summary>
+        protected override void OnTemplateApplied(TemplateAppliedEventArgs e)
+        {
+            base.OnTemplateApplied(e);
+            SetPseudoClasses();
+        }
+        
+        /// <summary>
+        /// Sets PseudoClasses based on current state.
+        /// </summary>
+        private void SetPseudoClasses()
+        {
+            PseudoClasses.Set(":selected", IsSelected);
+            PseudoClasses.Set(":inactive", IsInactive);
+            PseudoClasses.Set(":btnfocused", IsCalendarButtonFocused && IsEnabled);
+        }
+
+        /// <summary>
+        /// Occurs when the left mouse button is pressed (or when the tip of the
+        /// stylus touches the tablet PC) while the mouse pointer is over a
+        /// UIElement.
+        /// </summary>
+        public event EventHandler<PointerPressedEventArgs> CalendarLeftMouseButtonDown;
+
+        /// <summary>
+        /// Occurs when the left mouse button is released (or the tip of the
+        /// stylus is removed from the tablet PC) while the mouse (or the
+        /// stylus) is over a UIElement (or while a UIElement holds mouse
+        /// capture).
+        /// </summary>
+        public event EventHandler<PointerReleasedEventArgs> CalendarLeftMouseButtonUp;
+
+        /// <summary>
+        /// Provides class handling for the MouseLeftButtonDown event that
+        /// occurs when the left mouse button is pressed while the mouse pointer
+        /// is over this control.
+        /// </summary>
+        /// <param name="e">The event data. </param>
+        /// <exception cref="System.ArgumentNullException">
+        /// e is a null reference (Nothing in Visual Basic).
+        /// </exception>
+        /// <remarks>
+        /// This method marks the MouseLeftButtonDown event as handled by
+        /// setting the MouseButtonEventArgs.Handled property of the event data
+        /// to true when the button is enabled and its ClickMode is not set to
+        /// Hover.  Since this method marks the MouseLeftButtonDown event as
+        /// handled in some situations, you should use the Click event instead
+        /// to detect a button click.
+        /// </remarks>
+        protected override void OnPointerPressed(PointerPressedEventArgs e)
+        {
+            base.OnPointerPressed(e);
+            if (e.MouseButton == MouseButton.Left)
+                CalendarLeftMouseButtonDown?.Invoke(this, e);
+        }
+
+        /// <summary>
+        /// Provides handling for the MouseLeftButtonUp event that occurs when
+        /// the left mouse button is released while the mouse pointer is over
+        /// this control. 
+        /// </summary>
+        /// <param name="e">The event data.</param>
+        /// <exception cref="System.ArgumentNullException">
+        /// e is a null reference (Nothing in Visual Basic).
+        /// </exception>
+        /// <remarks>
+        /// This method marks the MouseLeftButtonUp event as handled by setting
+        /// the MouseButtonEventArgs.Handled property of the event data to true
+        /// when the button is enabled and its ClickMode is not set to Hover.
+        /// Since this method marks the MouseLeftButtonUp event as handled in
+        /// some situations, you should use the Click event instead to detect a
+        /// button click.
+        /// </remarks>
+        protected override void OnPointerReleased(PointerReleasedEventArgs e)
+        {
+            base.OnPointerReleased(e);
+            if (e.MouseButton == MouseButton.Left)
+                CalendarLeftMouseButtonUp?.Invoke(this, e);
+        }
+        
+        /// <summary>
+        /// We need to simulate the MouseLeftButtonUp event for the
+        /// CalendarButton that stays in Pressed state after MouseCapture is
+        /// released since there is no actual MouseLeftButtonUp event for the
+        /// release.
+        /// </summary>
+        /// <param name="e">Event arguments.</param>
+        internal void SendMouseLeftButtonUp(PointerReleasedEventArgs e)
+        {
+            e.Handled = false;
+            base.OnPointerReleased(e);
+        }
+    }
+}
diff --git a/src/Avalonia.Controls/Calendar/CalendarDateRange.cs b/src/Avalonia.Controls/Calendar/CalendarDateRange.cs
new file mode 100644
index 0000000000..273cda8c5b
--- /dev/null
+++ b/src/Avalonia.Controls/Calendar/CalendarDateRange.cs
@@ -0,0 +1,79 @@
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+
+using System;
+using System.Diagnostics;
+
+namespace Avalonia.Controls
+{
+    public sealed class CalendarDateRange
+    {
+        /// <summary>
+        /// Gets the first date in the represented range.
+        /// </summary>
+        /// <value>The first date in the represented range.</value>
+        public DateTime Start { get; private set; }
+
+        /// <summary>
+        /// Gets the last date in the represented range.
+        /// </summary>
+        /// <value>The last date in the represented range.</value>
+        public DateTime End { get; private set; }
+
+        /// <summary>
+        /// Initializes a new instance of the
+        /// <see cref="T:System.Windows.Controls.CalendarDateRange" /> class
+        /// with a single date.
+        /// </summary>
+        /// <param name="day">The date to be represented by the range.</param>
+        public CalendarDateRange(DateTime day)
+        {
+            Start = day;
+            End = day;
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the
+        /// <see cref="T:System.Windows.Controls.CalendarDateRange" /> class
+        /// with a range of dates.
+        /// </summary>
+        /// <param name="start">
+        /// The start of the range to be represented.
+        /// </param>
+        /// <param name="end">The end of the range to be represented.</param>
+        public CalendarDateRange(DateTime start, DateTime end)
+        {
+            if (DateTime.Compare(end, start) >= 0)
+            {
+                Start = start;
+                End = end;
+            }
+            else
+            {
+                // Always use the start for ranges on the same day
+                Start = start;
+                End = start;
+            }
+        }
+
+        /// <summary>
+        /// Returns true if any day in the given DateTime range is contained in
+        /// the current CalendarDateRange.
+        /// </summary>
+        /// <param name="range">Inherited code: Requires comment 1.</param>
+        /// <returns>Inherited code: Requires comment 2.</returns>
+        internal bool ContainsAny(CalendarDateRange range)
+        {
+            Debug.Assert(range != null, "range should not be null!");
+
+            int start = DateTime.Compare(Start, range.Start);
+
+            // Check if any part of the supplied range is contained by this
+            // range or if the supplied range completely covers this range.
+            return (start <= 0 && DateTime.Compare(End, range.Start) >= 0) ||
+                (start >= 0 && DateTime.Compare(Start, range.End) <= 0);
+        }
+    }
+}
diff --git a/src/Avalonia.Controls/Calendar/CalendarDayButton.cs b/src/Avalonia.Controls/Calendar/CalendarDayButton.cs
new file mode 100644
index 0000000000..f6d0fbba62
--- /dev/null
+++ b/src/Avalonia.Controls/Calendar/CalendarDayButton.cs
@@ -0,0 +1,253 @@
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+
+using Avalonia.Input;
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Text;
+
+namespace Avalonia.Controls.Primitives
+{
+    public sealed class CalendarDayButton : Button
+    {
+        /// <summary>
+        /// Default content for the CalendarDayButton.
+        /// </summary>
+        private const int DefaultContent = 1;
+
+        private bool _isCurrent;
+        private bool _ignoringMouseOverState;
+        private bool _isBlackout;
+        private bool _isToday;
+        private bool _isInactive;
+        private bool _isSelected;
+
+        /// <summary>
+        /// Initializes a new instance of the
+        /// <see cref="T:Avalonia.Controls.Primitives.CalendarDayButton" />
+        /// class.
+        /// </summary>
+        public CalendarDayButton()
+            : base()
+        {
+            //Focusable = false;
+            Content = DefaultContent.ToString(CultureInfo.CurrentCulture);
+        }
+
+        /// <summary>
+        /// Gets or sets the Calendar associated with this button.
+        /// </summary>
+        internal Calendar Owner { get; set; }
+        internal int Index { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the button is the focused
+        /// element on the Calendar control.
+        /// </summary>
+        internal bool IsCurrent
+        {
+            get { return _isCurrent; }
+            set
+            {
+                if (_isCurrent != value)
+                {
+                    _isCurrent = value;
+                    SetPseudoClasses();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Ensure the button is not in the MouseOver state.
+        /// </summary>
+        /// <remarks>
+        /// If a button is in the MouseOver state when a Popup is closed (as is
+        /// the case when you select a date in the DatePicker control), it will
+        /// continue to think it's in the mouse over state even when the Popup
+        /// opens again and it's not.  This method is used to forcibly clear the
+        /// state by changing the CommonStates state group.
+        /// </remarks>
+        internal void IgnoreMouseOverState()
+        {
+            // TODO: Investigate whether this needs to be done by changing the
+            // state everytime we change any state, or if it can be done once
+            // to properly reset the control.
+
+            _ignoringMouseOverState = false;
+
+            // If the button thinks it's in the MouseOver state (which can
+            // happen when a Popup is closed before the button can change state)
+            // we will override the state so it shows up as normal.
+            if (IsPointerOver)
+            {
+                _ignoringMouseOverState = true;
+                SetPseudoClasses();
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether this is a blackout date.
+        /// </summary>
+        internal bool IsBlackout
+        {
+            get { return _isBlackout; }
+            set
+            {
+                if (_isBlackout != value)
+                {
+                    _isBlackout = value;
+                    SetPseudoClasses();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether this button represents
+        /// today.
+        /// </summary>
+        internal bool IsToday
+        {
+            get { return _isToday; }
+            set
+            {
+                if (_isToday != value)
+                {
+                    _isToday = value;
+                    SetPseudoClasses();
+                }
+            }
+        }
+        /// <summary>
+        /// Gets or sets a value indicating whether the button is inactive.
+        /// </summary>
+        internal bool IsInactive
+        {
+            get { return _isInactive; }
+            set
+            {
+                if (_isInactive != value)
+                {
+                    _isInactive = value;
+                    SetPseudoClasses();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the button is selected.
+        /// </summary>
+        internal bool IsSelected
+        {
+            get { return _isSelected; }
+            set
+            {
+                if (_isSelected != value)
+                {
+                    _isSelected = value;
+                    SetPseudoClasses();
+                }
+            }
+        }
+
+        protected override void OnTemplateApplied(TemplateAppliedEventArgs e)
+        {
+            base.OnTemplateApplied(e);
+            SetPseudoClasses();
+        }
+        private void SetPseudoClasses()
+        {
+            if (_ignoringMouseOverState)
+            {
+                PseudoClasses.Set(":pressed", IsPressed);
+                PseudoClasses.Set(":disabled", !IsEnabled);
+            }
+
+            PseudoClasses.Set(":selected", IsSelected);
+            PseudoClasses.Set(":inactive", IsInactive);
+            PseudoClasses.Set(":today", IsToday);
+            PseudoClasses.Set(":blackout", IsBlackout);
+            PseudoClasses.Set(":dayfocused", IsCurrent && IsEnabled);
+        }
+
+        /// <summary>
+        /// Occurs when the left mouse button is pressed (or when the tip of the
+        /// stylus touches the tablet PC) while the mouse pointer is over a
+        /// UIElement.
+        /// </summary>
+        public event EventHandler<PointerPressedEventArgs> CalendarDayButtonMouseDown;
+
+        /// <summary>
+        /// Occurs when the left mouse button is released (or the tip of the
+        /// stylus is removed from the tablet PC) while the mouse (or the
+        /// stylus) is over a UIElement (or while a UIElement holds mouse
+        /// capture).
+        /// </summary>
+        public event EventHandler<PointerReleasedEventArgs> CalendarDayButtonMouseUp;
+
+        /// <summary>
+        /// Provides class handling for the MouseLeftButtonDown event that
+        /// occurs when the left mouse button is pressed while the mouse pointer
+        /// is over this control.
+        /// </summary>
+        /// <param name="e">The event data. </param>
+        /// <exception cref="System.ArgumentNullException">
+        /// e is a null reference (Nothing in Visual Basic).
+        /// </exception>
+        /// <remarks>
+        /// This method marks the MouseLeftButtonDown event as handled by
+        /// setting the MouseButtonEventArgs.Handled property of the event data
+        /// to true when the button is enabled and its ClickMode is not set to
+        /// Hover.  Since this method marks the MouseLeftButtonDown event as
+        /// handled in some situations, you should use the Click event instead
+        /// to detect a button click.
+        /// </remarks>
+        protected override void OnPointerPressed(PointerPressedEventArgs e)
+        {
+            base.OnPointerPressed(e);
+
+            if (e.MouseButton == MouseButton.Left)
+                CalendarDayButtonMouseDown?.Invoke(this, e);
+        }
+
+        /// <summary>
+        /// Provides handling for the MouseLeftButtonUp event that occurs when
+        /// the left mouse button is released while the mouse pointer is over
+        /// this control. 
+        /// </summary>
+        /// <param name="e">The event data.</param>
+        /// <exception cref="System.ArgumentNullException">
+        /// e is a null reference (Nothing in Visual Basic).
+        /// </exception>
+        /// <remarks>
+        /// This method marks the MouseLeftButtonUp event as handled by setting
+        /// the MouseButtonEventArgs.Handled property of the event data to true
+        /// when the button is enabled and its ClickMode is not set to Hover.
+        /// Since this method marks the MouseLeftButtonUp event as handled in
+        /// some situations, you should use the Click event instead to detect a
+        /// button click.
+        /// </remarks>
+        protected override void OnPointerReleased(PointerReleasedEventArgs e)
+        {
+            base.OnPointerReleased(e);
+
+            if (e.MouseButton == MouseButton.Left)
+                CalendarDayButtonMouseUp?.Invoke(this, e);
+        }
+
+        /// <summary>
+        /// We need to simulate the MouseLeftButtonUp event for the
+        /// CalendarDayButton that stays in Pressed state after MouseCapture is
+        /// released since there is no actual MouseLeftButtonUp event for the
+        /// release.
+        /// </summary>
+        /// <param name="e">Event arguments.</param>
+        internal void SendMouseLeftButtonUp(PointerReleasedEventArgs e)
+        {
+            e.Handled = false;
+            base.OnPointerReleased(e);
+        }
+    }
+}
diff --git a/src/Avalonia.Controls/Calendar/CalendarExtensions.cs b/src/Avalonia.Controls/Calendar/CalendarExtensions.cs
new file mode 100644
index 0000000000..4fda02bff3
--- /dev/null
+++ b/src/Avalonia.Controls/Calendar/CalendarExtensions.cs
@@ -0,0 +1,21 @@
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+
+using System;
+using System.Collections.Generic;
+using Avalonia.Input;
+using System.Diagnostics;
+
+namespace Avalonia.Controls.Primitives
+{
+    internal static class CalendarExtensions
+    {
+        public static void GetMetaKeyState(InputModifiers modifiers, out bool ctrl, out bool shift)
+        {
+            ctrl = (modifiers & InputModifiers.Control) == InputModifiers.Control;
+            shift = (modifiers & InputModifiers.Shift) == InputModifiers.Shift;
+        }
+    }
+}
diff --git a/src/Avalonia.Controls/Calendar/CalendarItem.cs b/src/Avalonia.Controls/Calendar/CalendarItem.cs
new file mode 100644
index 0000000000..3432fa549d
--- /dev/null
+++ b/src/Avalonia.Controls/Calendar/CalendarItem.cs
@@ -0,0 +1,1264 @@
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+
+using Avalonia.Data;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.Media;
+using System;
+using System.Diagnostics;
+using System.Globalization;
+
+namespace Avalonia.Controls.Primitives
+{
+    /// <summary>
+    /// Represents the currently displayed month or year on a
+    /// <see cref="T:Avalonia.Controls.Calendar" />.
+    /// </summary>
+    public sealed class CalendarItem : TemplatedControl
+    {
+        /// <summary>
+        /// The number of days per week.
+        /// </summary>
+        private const int NumberOfDaysPerWeek = 7;
+
+        private const string PART_ElementHeaderButton = "HeaderButton";
+        private const string PART_ElementPreviousButton = "PreviousButton";
+        private const string PART_ElementNextButton = "NextButton";
+        private const string PART_ElementMonthView = "MonthView";
+        private const string PART_ElementYearView = "YearView";
+
+        private Button _headerButton;
+        private Button _nextButton;
+        private Button _previousButton;
+        private Grid _monthView;
+        private Grid _yearView;
+        private ITemplate<IControl> _dayTitleTemplate;
+        private CalendarButton _lastCalendarButton;
+        private CalendarDayButton _lastCalendarDayButton;
+        
+        private DateTime _currentMonth;
+        private bool _isMouseLeftButtonDown = false;
+        private bool _isMouseLeftButtonDownYearView = false;
+        private bool _isControlPressed = false;
+
+        private System.Globalization.Calendar _calendar = new System.Globalization.GregorianCalendar();
+
+        private PointerPressedEventArgs _downEventArg;
+        private PointerPressedEventArgs _downEventArgYearView;
+
+        internal Calendar Owner { get; set; }
+        internal CalendarDayButton CurrentButton { get; set; }
+
+        public static StyledProperty<IBrush> HeaderBackgroundProperty = Calendar.HeaderBackgroundProperty.AddOwner<CalendarItem>();
+        public IBrush HeaderBackground
+        {
+            get { return GetValue(HeaderBackgroundProperty); }
+            set { SetValue(HeaderBackgroundProperty, value); }
+        }
+        public static readonly DirectProperty<CalendarItem, ITemplate<IControl>> DayTitleTemplateProperty =
+                AvaloniaProperty.RegisterDirect<CalendarItem, ITemplate<IControl>>(
+                    nameof(DayTitleTemplate),
+                    o => o.DayTitleTemplate,
+                    (o,v) => o.DayTitleTemplate = v,
+                    defaultBindingMode: BindingMode.OneTime);
+        public ITemplate<IControl> DayTitleTemplate
+        {
+            get { return _dayTitleTemplate; }
+            set { SetAndRaise(DayTitleTemplateProperty, ref _dayTitleTemplate, value); }
+        }
+
+        /// <summary>
+        /// Gets the button that allows switching between month mode, year mode,
+        /// and decade mode. 
+        /// </summary>
+        internal Button HeaderButton
+        {
+            get { return _headerButton; }
+            private set
+            {
+                if (_headerButton != null)
+                    _headerButton.Click -= HeaderButton_Click;
+
+                _headerButton = value;
+
+                if (_headerButton != null)
+                {
+                    _headerButton.Click += HeaderButton_Click;
+                    _headerButton.Focusable = false;
+                }
+            }
+        }
+        /// <summary>
+        /// Gets the button that displays the next page of the calendar when it
+        /// is clicked.
+        /// </summary>
+        internal Button NextButton
+        {
+            get { return _nextButton; }
+            private set
+            {
+                if (_nextButton != null)
+                    _nextButton.Click -= NextButton_Click;
+
+                _nextButton = value;
+
+                if (_nextButton != null)
+                {
+                    // If the user does not provide a Content value in template,
+                    // we provide a helper text that can be used in
+                    // Accessibility this text is not shown on the UI, just used
+                    // for Accessibility purposes
+                    if (_nextButton.Content == null)
+                    {
+                        _nextButton.Content = "next button";
+                    }
+
+                    _nextButton.IsVisible = true;
+                    _nextButton.Click += NextButton_Click;
+                    _nextButton.Focusable = false;
+                }
+            }
+        }
+        /// <summary>
+        /// Gets the button that displays the previous page of the calendar when
+        /// it is clicked.
+        /// </summary>
+        internal Button PreviousButton
+        {
+            get { return _previousButton; }
+            private set
+            {
+                if (_previousButton != null)
+                    _previousButton.Click -= PreviousButton_Click;
+
+                _previousButton = value;
+
+                if (_previousButton != null)
+                {
+                    // If the user does not provide a Content value in template,
+                    // we provide a helper text that can be used in
+                    // Accessibility this text is not shown on the UI, just used
+                    // for Accessibility purposes
+                    if (_previousButton.Content == null)
+                    {
+                        _previousButton.Content = "previous button";
+                    }
+
+                    _previousButton.IsVisible = true;
+                    _previousButton.Click += PreviousButton_Click;
+                    _previousButton.Focusable = false;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets the Grid that hosts the content when in month mode.
+        /// </summary>
+        internal Grid MonthView
+        {
+            get { return _monthView; }
+            private set
+            {
+                if (_monthView != null)
+                    _monthView.PointerLeave -= MonthView_MouseLeave;
+
+                _monthView = value;
+
+                if (_monthView != null)
+                    _monthView.PointerLeave += MonthView_MouseLeave;
+            }
+        }
+        /// <summary>
+        /// Gets the Grid that hosts the content when in year or decade mode.
+        /// </summary>
+        internal Grid YearView
+        {
+            get { return _yearView; }
+            private set
+            {
+                if (_yearView != null)
+                    _yearView.PointerLeave -= YearView_MouseLeave;
+
+                _yearView = value;
+
+                if (_yearView != null)
+                    _yearView.PointerLeave += YearView_MouseLeave;
+            }
+        }
+
+        private void PopulateGrids()
+        {
+            if (MonthView != null)
+            {
+                for (int i = 0; i < Calendar.RowsPerMonth; i++)
+                {
+                    if (_dayTitleTemplate != null)
+                    {
+                        var cell = _dayTitleTemplate.Build();
+                        cell.DataContext = string.Empty;
+                        cell.SetValue(Grid.RowProperty, 0);
+                        cell.SetValue(Grid.ColumnProperty, i);
+                        MonthView.Children.Add(cell);
+                    }
+                }
+
+                for (int i = 1; i < Calendar.RowsPerMonth; i++)
+                {
+                    for (int j = 0; j < Calendar.ColumnsPerMonth; j++)
+                    {
+                        CalendarDayButton cell = new CalendarDayButton();
+
+                        if (Owner != null)
+                        {
+                            cell.Owner = Owner;
+                        }
+                        cell.SetValue(Grid.RowProperty, i);
+                        cell.SetValue(Grid.ColumnProperty, j);
+                        cell.CalendarDayButtonMouseDown += Cell_MouseLeftButtonDown;
+                        cell.CalendarDayButtonMouseUp += Cell_MouseLeftButtonUp;
+                        cell.PointerEnter += Cell_MouseEnter;
+                        cell.PointerLeave += Cell_MouseLeave;
+                        cell.Click += Cell_Click;
+                        MonthView.Children.Add(cell);
+                    }
+                }
+            }
+
+            if (YearView != null)
+            {
+                CalendarButton month;
+                for (int i = 0; i < Calendar.RowsPerYear; i++)
+                {
+                    for (int j = 0; j < Calendar.ColumnsPerYear; j++)
+                    {
+                        month = new CalendarButton();
+
+                        if (Owner != null)
+                        {
+                            month.Owner = Owner;
+                        }
+                        month.SetValue(Grid.RowProperty, i);
+                        month.SetValue(Grid.ColumnProperty, j);
+                        month.CalendarLeftMouseButtonDown += Month_CalendarButtonMouseDown;
+                        month.CalendarLeftMouseButtonUp += Month_CalendarButtonMouseUp;
+                        month.PointerEnter += Month_MouseEnter;
+                        month.PointerLeave += Month_MouseLeave;
+                        YearView.Children.Add(month);
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Builds the visual tree for the
+        /// <see cref="T:System.Windows.Controls.Primitives.CalendarItem" />
+        /// when a new template is applied.
+        /// </summary>
+        protected override void OnTemplateApplied(TemplateAppliedEventArgs e)
+        {
+            base.OnTemplateApplied(e);
+            
+            HeaderButton = e.NameScope.Find<Button>(PART_ElementHeaderButton);
+            PreviousButton = e.NameScope.Find<Button>(PART_ElementPreviousButton);
+            NextButton = e.NameScope.Find<Button>(PART_ElementNextButton);
+            MonthView = e.NameScope.Find<Grid>(PART_ElementMonthView);
+            YearView = e.NameScope.Find<Grid>(PART_ElementYearView);
+            
+            if (Owner != null)
+            {
+                UpdateDisabled(Owner.IsEnabled);
+            }
+
+            PopulateGrids();
+
+            if (MonthView != null && YearView != null)
+            {
+                if (Owner != null)
+                {
+                    Owner.SelectedMonth = Owner.DisplayDateInternal;
+                    Owner.SelectedYear = Owner.DisplayDateInternal;
+
+                    if (Owner.DisplayMode == CalendarMode.Year)
+                    {
+                        UpdateYearMode();
+                    }
+                    else if (Owner.DisplayMode == CalendarMode.Decade)
+                    {
+                        UpdateDecadeMode();
+                    }
+
+                    if (Owner.DisplayMode == CalendarMode.Month)
+                    {
+                        UpdateMonthMode();
+                        MonthView.IsVisible = true;
+                        YearView.IsVisible = false;
+                    }
+                    else
+                    {
+                        YearView.IsVisible = true;
+                        MonthView.IsVisible = false;
+                    }
+                }
+                else
+                {
+                    UpdateMonthMode();
+                    MonthView.IsVisible = true;
+                    YearView.IsVisible = false;
+                }
+            }
+        }
+
+        private void SetDayTitles()
+        {
+            for (int childIndex = 0; childIndex < Calendar.ColumnsPerMonth; childIndex++)
+            {
+                var daytitle = MonthView.Children[childIndex];
+                if (daytitle != null)
+                {
+                    if (Owner != null)
+                    {
+                        daytitle.DataContext = DateTimeHelper.GetCurrentDateFormat().ShortestDayNames[(childIndex + (int)Owner.FirstDayOfWeek) % NumberOfDaysPerWeek];
+                    }
+                    else
+                    {
+                        daytitle.DataContext = DateTimeHelper.GetCurrentDateFormat().ShortestDayNames[(childIndex + (int)DateTimeHelper.GetCurrentDateFormat().FirstDayOfWeek) % NumberOfDaysPerWeek];
+                    }
+                }
+            }
+        }
+        /// <summary>
+        /// How many days of the previous month need to be displayed.
+        /// </summary>
+        private int PreviousMonthDays(DateTime firstOfMonth)
+        {
+            DayOfWeek day = _calendar.GetDayOfWeek(firstOfMonth);
+            int i;
+
+            if (Owner != null)
+            {
+                i = ((day - Owner.FirstDayOfWeek + NumberOfDaysPerWeek) % NumberOfDaysPerWeek);
+            }
+            else
+            {
+                i = ((day - DateTimeHelper.GetCurrentDateFormat().FirstDayOfWeek + NumberOfDaysPerWeek) % NumberOfDaysPerWeek);
+            }
+
+            if (i == 0)
+            {
+                return NumberOfDaysPerWeek;
+            }
+            else
+            {
+                return i;
+            }
+        }
+
+        internal void UpdateMonthMode()
+        {
+            if (Owner != null)
+            {
+                Debug.Assert(Owner.DisplayDate != null, "The Owner Calendar's DisplayDate should not be null!");
+                _currentMonth = Owner.DisplayDateInternal;
+            }
+            else
+            {
+                _currentMonth = DateTime.Today;
+            }
+
+            if (_currentMonth != null)
+            {
+                SetMonthModeHeaderButton();
+                SetMonthModePreviousButton(_currentMonth);
+                SetMonthModeNextButton(_currentMonth);
+
+                if (MonthView != null)
+                {
+                    SetDayTitles();
+                    SetCalendarDayButtons(_currentMonth);
+                }
+            }
+        }
+        private void SetMonthModeHeaderButton()
+        {
+            if (HeaderButton != null)
+            {
+                if (Owner != null)
+                {
+                    HeaderButton.Content = Owner.DisplayDateInternal.ToString("Y", DateTimeHelper.GetCurrentDateFormat());
+                    HeaderButton.IsEnabled = true;
+                }
+                else
+                {
+                    HeaderButton.Content = DateTime.Today.ToString("Y", DateTimeHelper.GetCurrentDateFormat());
+                }
+            }
+        }
+        private void SetMonthModeNextButton(DateTime firstDayOfMonth)
+        {
+            if (Owner != null && NextButton != null)
+            {
+                // DisplayDate is equal to DateTime.MaxValue
+                if (DateTimeHelper.CompareYearMonth(firstDayOfMonth, DateTime.MaxValue) == 0)
+                {
+                    NextButton.IsEnabled = false;
+                }
+                else
+                {
+                    // Since we are sure DisplayDate is not equal to
+                    // DateTime.MaxValue, it is safe to use AddMonths  
+                    DateTime firstDayOfNextMonth = _calendar.AddMonths(firstDayOfMonth, 1);
+                    NextButton.IsEnabled = (DateTimeHelper.CompareDays(Owner.DisplayDateRangeEnd, firstDayOfNextMonth) > -1);
+                }
+            }
+        }
+        private void SetMonthModePreviousButton(DateTime firstDayOfMonth)
+        {
+            if (Owner != null && PreviousButton != null)
+            {
+                PreviousButton.IsEnabled = (DateTimeHelper.CompareDays(Owner.DisplayDateRangeStart, firstDayOfMonth) < 0);
+            }
+        }
+
+        private void SetButtonState(CalendarDayButton childButton, DateTime dateToAdd)
+        {
+            if (Owner != null)
+            {
+                childButton.Opacity = 1;
+
+                // If the day is outside the DisplayDateStart/End boundary, do
+                // not show it
+                if (DateTimeHelper.CompareDays(dateToAdd, Owner.DisplayDateRangeStart) < 0 || DateTimeHelper.CompareDays(dateToAdd, Owner.DisplayDateRangeEnd) > 0)
+                {
+                    childButton.IsEnabled = false;
+                    childButton.IsToday = false;
+                    childButton.IsSelected = false;
+                    childButton.Opacity = 0;
+                }
+                else
+                {
+                    // SET IF THE DAY IS SELECTABLE OR NOT
+                    if (Owner.BlackoutDates.Contains(dateToAdd))
+                    {
+                        childButton.IsBlackout = true;
+                    }
+                    else
+                    {
+                        childButton.IsBlackout = false;
+                    }
+                    childButton.IsEnabled = true;
+
+                    // SET IF THE DAY IS INACTIVE OR NOT: set if the day is a
+                    // trailing day or not
+                    childButton.IsInactive = (DateTimeHelper.CompareYearMonth(dateToAdd, Owner.DisplayDateInternal) != 0);
+
+                    // SET IF THE DAY IS TODAY OR NOT
+                    childButton.IsToday = (Owner.IsTodayHighlighted && dateToAdd == DateTime.Today);
+
+                    // SET IF THE DAY IS SELECTED OR NOT
+                    childButton.IsSelected = false;
+                    foreach (DateTime item in Owner.SelectedDates)
+                    {
+                        // Since we should be comparing the Date values not
+                        // DateTime values, we can't use
+                        // Owner.SelectedDates.Contains(dateToAdd) directly
+                        childButton.IsSelected |= (DateTimeHelper.CompareDays(dateToAdd, item) == 0);
+                    }
+
+                    // SET THE FOCUS ELEMENT
+                    if (Owner.LastSelectedDate != null)
+                    {
+                        if (DateTimeHelper.CompareDays(Owner.LastSelectedDate.Value, dateToAdd) == 0)
+                        {
+                            if (Owner.FocusButton != null)
+                            {
+                                Owner.FocusButton.IsCurrent = false;
+                            }
+                            Owner.FocusButton = childButton;
+                            if (Owner.HasFocusInternal)
+                            {
+                                Owner.FocusButton.IsCurrent = true;
+                            }
+                        }
+                        else
+                        {
+                            childButton.IsCurrent = false;
+                        }
+                    }
+                }
+            }
+        }
+        private void SetCalendarDayButtons(DateTime firstDayOfMonth)
+        {
+            int lastMonthToDisplay = PreviousMonthDays(firstDayOfMonth);
+            DateTime dateToAdd;
+
+            if (DateTimeHelper.CompareYearMonth(firstDayOfMonth, DateTime.MinValue) > 0)
+            {
+                // DisplayDate is not equal to DateTime.MinValue we can subtract
+                // days from the DisplayDate
+                dateToAdd = _calendar.AddDays(firstDayOfMonth, -lastMonthToDisplay);
+            }
+            else
+            {
+                dateToAdd = firstDayOfMonth;
+            }
+
+            if (Owner != null && Owner.HoverEnd != null && Owner.HoverStart != null)
+            {
+                Owner.HoverEndIndex = null;
+                Owner.HoverStartIndex = null;
+            }
+
+            int count = Calendar.RowsPerMonth * Calendar.ColumnsPerMonth;
+
+            for (int childIndex = Calendar.ColumnsPerMonth; childIndex < count; childIndex++)
+            {
+                CalendarDayButton childButton = MonthView.Children[childIndex] as CalendarDayButton;
+                Debug.Assert(childButton != null, "childButton should not be null!");
+
+                childButton.Index = childIndex;
+                SetButtonState(childButton, dateToAdd);
+
+                // Update the indexes of hoverStart and hoverEnd
+                if (Owner != null && Owner.HoverEnd != null && Owner.HoverStart != null)
+                {
+                    if (DateTimeHelper.CompareDays(dateToAdd, Owner.HoverEnd.Value) == 0)
+                    {
+                        Owner.HoverEndIndex = childIndex;
+                    }
+
+                    if (DateTimeHelper.CompareDays(dateToAdd, Owner.HoverStart.Value) == 0)
+                    {
+                        Owner.HoverStartIndex = childIndex;
+                    }
+                }
+
+                //childButton.Focusable = false;
+                childButton.Content = dateToAdd.Day.ToString(DateTimeHelper.GetCurrentDateFormat());
+                childButton.DataContext = dateToAdd;
+
+                if (DateTime.Compare((DateTime)DateTimeHelper.DiscardTime(DateTime.MaxValue), dateToAdd) > 0)
+                {
+                    // Since we are sure DisplayDate is not equal to
+                    // DateTime.MaxValue, it is safe to use AddDays 
+                    dateToAdd = _calendar.AddDays(dateToAdd, 1);
+                }
+                else
+                {
+                    // DisplayDate is equal to the DateTime.MaxValue, so there
+                    // are no trailing days
+                    childIndex++;
+                    for (int i = childIndex; i < count; i++)
+                    {
+                        childButton = MonthView.Children[i] as CalendarDayButton;
+                        Debug.Assert(childButton != null, "childButton should not be null!");
+                        // button needs a content to occupy the necessary space
+                        // for the content presenter
+                        childButton.Content = i.ToString(DateTimeHelper.GetCurrentDateFormat());
+                        childButton.IsEnabled = false;
+                        childButton.Opacity = 0;
+                    }
+                    return;
+                }
+            }
+
+            // If the HoverStart or HoverEndInternal could not be found on the
+            // DisplayMonth set the values of the HoverStartIndex or
+            // HoverEndIndex to be the first or last day indexes on the current
+            // month
+            if (Owner != null && Owner.HoverStart.HasValue && Owner.HoverEndInternal.HasValue)
+            {
+                if (!Owner.HoverEndIndex.HasValue)
+                {
+                    if (DateTimeHelper.CompareDays(Owner.HoverEndInternal.Value, Owner.HoverStart.Value) > 0)
+                    {
+                        Owner.HoverEndIndex = Calendar.ColumnsPerMonth * Calendar.RowsPerMonth - 1;
+                    }
+                    else
+                    {
+                        Owner.HoverEndIndex = Calendar.ColumnsPerMonth;
+                    }
+                }
+
+                if (!Owner.HoverStartIndex.HasValue)
+                {
+                    if (DateTimeHelper.CompareDays(Owner.HoverEndInternal.Value, Owner.HoverStart.Value) > 0)
+                    {
+                        Owner.HoverStartIndex = Calendar.ColumnsPerMonth;
+                    }
+                    else
+                    {
+                        Owner.HoverStartIndex = Calendar.ColumnsPerMonth * Calendar.RowsPerMonth - 1;
+                    }
+                }
+            }
+        }
+
+        internal void UpdateYearMode()
+        {
+            if (Owner != null)
+            {
+                Debug.Assert(Owner.SelectedMonth != null, "The Owner Calendar's SelectedMonth should not be null!");
+                _currentMonth = (DateTime)Owner.SelectedMonth;
+            }
+            else
+            {
+                _currentMonth = DateTime.Today;
+            }
+
+            if (_currentMonth != null)
+            {
+                SetYearModeHeaderButton();
+                SetYearModePreviousButton();
+                SetYearModeNextButton();
+
+                if (YearView != null)
+                {
+                    SetMonthButtonsForYearMode();
+                }
+            }
+        }
+        private void SetYearModeHeaderButton()
+        {
+            if (HeaderButton != null)
+            {
+                HeaderButton.IsEnabled = true;
+                HeaderButton.Content = _currentMonth.Year.ToString(DateTimeHelper.GetCurrentDateFormat());
+            }
+        }
+        private void SetYearModePreviousButton()
+        {
+            if (Owner != null && PreviousButton != null)
+            {
+                PreviousButton.IsEnabled = (Owner.DisplayDateRangeStart.Year != _currentMonth.Year);
+            }
+        }
+        private void SetYearModeNextButton()
+        {
+            if (Owner != null && NextButton != null)
+            {
+                NextButton.IsEnabled = (Owner.DisplayDateRangeEnd.Year != _currentMonth.Year);
+            }
+        }
+
+        private void SetMonthButtonsForYearMode()
+        {
+            int count = 0;
+            foreach (object child in YearView.Children)
+            {
+                CalendarButton childButton = child as CalendarButton;
+                Debug.Assert(childButton != null, "childButton should not be null!");
+                // There should be no time component. Time is 12:00 AM
+                DateTime day = new DateTime(_currentMonth.Year, count + 1, 1);
+                childButton.DataContext = day;
+
+                childButton.Content = DateTimeHelper.GetCurrentDateFormat().AbbreviatedMonthNames[count];
+                childButton.IsVisible = true;
+
+                if (Owner != null)
+                {
+                    if (day.Year == _currentMonth.Year && day.Month == _currentMonth.Month && day.Day == _currentMonth.Day)
+                    {
+                        Owner.FocusCalendarButton = childButton;
+                        childButton.IsCalendarButtonFocused = Owner.HasFocusInternal;
+                    }
+                    else
+                    {
+                        childButton.IsCalendarButtonFocused = false;
+                    }
+
+                    Debug.Assert(Owner.DisplayDateInternal != null, "The Owner Calendar's DisplayDateInternal should not be null!");
+                    childButton.IsSelected = (DateTimeHelper.CompareYearMonth(day, Owner.DisplayDateInternal) == 0);
+
+                    if (DateTimeHelper.CompareYearMonth(day, Owner.DisplayDateRangeStart) < 0 || DateTimeHelper.CompareYearMonth(day, Owner.DisplayDateRangeEnd) > 0)
+                    {
+                        childButton.IsEnabled = false;
+                        childButton.Opacity = 0;
+                    }
+                    else
+                    {
+                        childButton.IsEnabled = true;
+                        childButton.Opacity = 1;
+                    }
+                }
+
+                childButton.IsInactive = false;
+                count++;
+            }
+        }
+        internal void UpdateDecadeMode()
+        {
+            DateTime selectedYear;
+
+            if (Owner != null)
+            {
+                Debug.Assert(Owner.SelectedYear != null, "The owning Calendar's selected year should not be null!");
+                selectedYear = Owner.SelectedYear;
+                _currentMonth = (DateTime)Owner.SelectedMonth;
+            }
+            else
+            {
+                _currentMonth = DateTime.Today;
+                selectedYear = DateTime.Today;
+            }
+
+            if (_currentMonth != null)
+            {
+                int decade = DateTimeHelper.DecadeOfDate(selectedYear);
+                int decadeEnd = DateTimeHelper.EndOfDecade(selectedYear);
+
+                SetDecadeModeHeaderButton(decade, decadeEnd);
+                SetDecadeModePreviousButton(decade);
+                SetDecadeModeNextButton(decadeEnd);
+
+                if (YearView != null)
+                {
+                    SetYearButtons(decade, decadeEnd);
+                }
+            }
+        }
+        internal void UpdateYearViewSelection(CalendarButton calendarButton)
+        {
+            if (Owner != null && calendarButton != null && calendarButton.DataContext != null)
+            {
+                Owner.FocusCalendarButton.IsCalendarButtonFocused = false;
+                Owner.FocusCalendarButton = calendarButton;
+                calendarButton.IsCalendarButtonFocused = Owner.HasFocusInternal;
+
+                if (Owner.DisplayMode == CalendarMode.Year)
+                {
+                    Owner.SelectedMonth = (DateTime)calendarButton.DataContext;
+                }
+                else
+                {
+                    Owner.SelectedYear = (DateTime)calendarButton.DataContext;
+                }
+            }
+        }
+
+        private void SetYearButtons(int decade, int decadeEnd)
+        {
+            int year;
+            int count = -1;
+            foreach (object child in YearView.Children)
+            {
+                CalendarButton childButton = child as CalendarButton;
+                Debug.Assert(childButton != null, "childButton should not be null!");
+                year = decade + count;
+
+                if (year <= DateTime.MaxValue.Year && year >= DateTime.MinValue.Year)
+                {
+                    // There should be no time component. Time is 12:00 AM
+                    DateTime day = new DateTime(year, 1, 1);
+                    childButton.DataContext = day;
+                    childButton.Content = year.ToString(DateTimeHelper.GetCurrentDateFormat());
+                    childButton.IsVisible = true;
+
+                    if (Owner != null)
+                    {
+                        if (year == Owner.SelectedYear.Year)
+                        {
+                            Owner.FocusCalendarButton = childButton;
+                            childButton.IsCalendarButtonFocused = Owner.HasFocusInternal;
+                        }
+                        else
+                        {
+                            childButton.IsCalendarButtonFocused = false;
+                        }
+                        childButton.IsSelected = (Owner.DisplayDate.Year == year);
+
+                        if (year < Owner.DisplayDateRangeStart.Year || year > Owner.DisplayDateRangeEnd.Year)
+                        {
+                            childButton.IsEnabled = false;
+                            childButton.Opacity = 0;
+                        }
+                        else
+                        {
+                            childButton.IsEnabled = true;
+                            childButton.Opacity = 1;
+                        }
+                    }
+
+                    // SET IF THE YEAR IS INACTIVE OR NOT: set if the year is a
+                    // trailing year or not
+                    childButton.IsInactive = (year < decade || year > decadeEnd);
+                }
+                else
+                {
+                    childButton.IsEnabled = false;
+                    childButton.Opacity = 0;
+                }
+
+                count++;
+            }
+        }
+        private void SetDecadeModeHeaderButton(int decade, int decadeEnd)
+        {
+            if (HeaderButton != null)
+            {
+                HeaderButton.Content = decade.ToString(CultureInfo.CurrentCulture) + "-" + decadeEnd.ToString(CultureInfo.CurrentCulture);
+                HeaderButton.IsEnabled = false;
+            }
+        }
+        private void SetDecadeModeNextButton(int decadeEnd)
+        {
+            if (Owner != null && NextButton != null)
+            {
+                NextButton.IsEnabled = (Owner.DisplayDateRangeEnd.Year > decadeEnd);
+            }
+        }
+        private void SetDecadeModePreviousButton(int decade)
+        {
+            if (Owner != null && PreviousButton != null)
+            {
+                PreviousButton.IsEnabled = (decade > Owner.DisplayDateRangeStart.Year);
+            }
+        }
+
+        internal void HeaderButton_Click(object sender, RoutedEventArgs e)
+        {
+            if (Owner != null)
+            {
+                if (!Owner.HasFocusInternal)
+                {
+                    Owner.Focus();
+                }
+                Button b = sender as Button;
+                DateTime d;
+
+                if (b.IsEnabled)
+                {
+                    if (Owner.DisplayMode == CalendarMode.Month)
+                    {
+                        if (Owner.DisplayDate != null)
+                        {
+                            d = Owner.DisplayDateInternal;
+                            Owner.SelectedMonth = new DateTime(d.Year, d.Month, 1);
+                        }
+                        Owner.DisplayMode = CalendarMode.Year;
+                    }
+                    else
+                    {
+                        Debug.Assert(Owner.DisplayMode == CalendarMode.Year, "The Owner Calendar's DisplayMode should be Year!");
+
+                        if (Owner.SelectedMonth != null)
+                        {
+                            d = Owner.SelectedMonth;
+                            Owner.SelectedYear = new DateTime(d.Year, d.Month, 1);
+                        }
+                        Owner.DisplayMode = CalendarMode.Decade;
+                    }
+                }
+            }
+        }
+        internal void PreviousButton_Click(object sender, RoutedEventArgs e)
+        {
+            if (Owner != null)
+            {
+                if (!Owner.HasFocusInternal)
+                {
+                    Owner.Focus();
+                }
+
+                Button b = sender as Button;
+                if (b.IsEnabled)
+                {
+                    Owner.OnPreviousClick();
+                }
+            }
+        }
+        internal void NextButton_Click(object sender, RoutedEventArgs e)
+        {
+            if (Owner != null)
+            {
+                if (!Owner.HasFocusInternal)
+                {
+                    Owner.Focus();
+                }
+                Button b = sender as Button;
+
+                if (b.IsEnabled)
+                {
+                    Owner.OnNextClick();
+                }
+            }
+        }
+
+        internal void Cell_MouseEnter(object sender, PointerEventArgs e)
+        {
+            if (Owner != null)
+            {
+                CalendarDayButton b = sender as CalendarDayButton;
+                if (_isMouseLeftButtonDown && b != null && b.IsEnabled && !b.IsBlackout)
+                {
+                    // Update the states of all buttons to be selected starting
+                    // from HoverStart to b
+                    switch (Owner.SelectionMode)
+                    {
+                        case CalendarSelectionMode.SingleDate:
+                            {
+                                DateTime selectedDate = (DateTime)b.DataContext;
+                                Owner.DatePickerDisplayDateFlag = true;
+                                if (Owner.SelectedDates.Count == 0)
+                                {
+                                    Owner.SelectedDates.Add(selectedDate);
+                                }
+                                else
+                                {
+                                    Owner.SelectedDates[0] = selectedDate;
+                                }
+                                return;
+                            }
+                        case CalendarSelectionMode.SingleRange:
+                        case CalendarSelectionMode.MultipleRange:
+                            {
+                                Debug.Assert(b.DataContext != null, "The DataContext should not be null!");
+                                Owner.UnHighlightDays();
+                                Owner.HoverEndIndex = b.Index;
+                                Owner.HoverEnd = (DateTime)b.DataContext;
+                                // Update the States of the buttons
+                                Owner.HighlightDays();
+                                return;
+                            }
+                    }
+                }
+            }
+        }
+        internal void Cell_MouseLeave(object sender, PointerEventArgs e)
+        {
+            if (_isMouseLeftButtonDown)
+            {
+                CalendarDayButton b = sender as CalendarDayButton;
+                // The button is in Pressed state. Change the state to normal.
+                if (e.Device.Captured == b)
+                    e.Device.Capture(null);
+                // null check is added for unit tests
+                if (_downEventArg != null)
+                {
+                    var arg =
+                        new PointerReleasedEventArgs()
+                        {
+                            Device = _downEventArg.Device,
+                            MouseButton = _downEventArg.MouseButton,
+                            Handled = _downEventArg.Handled,
+                            InputModifiers = _downEventArg.InputModifiers,
+                            Route = _downEventArg.Route,
+                            Source = _downEventArg.Source
+                        };
+
+                    b.SendMouseLeftButtonUp(arg);
+                }
+                _lastCalendarDayButton = b;
+            }
+        }
+        internal void Cell_MouseLeftButtonDown(object sender, PointerPressedEventArgs e)
+        {
+            if (Owner != null)
+            {
+                if (!Owner.HasFocusInternal)
+                {
+                    Owner.Focus();
+                }
+
+                bool ctrl, shift;
+                CalendarExtensions.GetMetaKeyState(e.InputModifiers, out ctrl, out shift);
+                CalendarDayButton b = sender as CalendarDayButton;
+
+                if (b != null)
+                {
+                    _isControlPressed = ctrl;
+                    if (b.IsEnabled && !b.IsBlackout)
+                    {
+                        DateTime selectedDate = (DateTime)b.DataContext;
+                        Debug.Assert(selectedDate != null, "selectedDate should not be null!");
+                        _isMouseLeftButtonDown = true;
+                        // null check is added for unit tests
+                        if (e != null)
+                        {
+                            _downEventArg = e;
+                        }
+
+                        switch (Owner.SelectionMode)
+                        {
+                            case CalendarSelectionMode.None:
+                                {
+                                    return;
+                                }
+                            case CalendarSelectionMode.SingleDate:
+                                {
+                                    Owner.DatePickerDisplayDateFlag = true;
+                                    if (Owner.SelectedDates.Count == 0)
+                                    {
+                                        Owner.SelectedDates.Add(selectedDate);
+                                    }
+                                    else
+                                    {
+                                        Owner.SelectedDates[0] = selectedDate;
+                                    }
+                                    return;
+                                }
+                            case CalendarSelectionMode.SingleRange:
+                                {
+                                    // Set the start or end of the selection
+                                    // range
+                                    if (shift)
+                                    {
+                                        Owner.UnHighlightDays();
+                                        Owner.HoverEnd = selectedDate;
+                                        Owner.HoverEndIndex = b.Index;
+                                        Owner.HighlightDays();
+                                    }
+                                    else
+                                    {
+                                        Owner.UnHighlightDays();
+                                        Owner.HoverStart = selectedDate;
+                                        Owner.HoverStartIndex = b.Index;
+                                    }
+                                    return;
+                                }
+                            case CalendarSelectionMode.MultipleRange:
+                                {
+                                    if (shift)
+                                    {
+                                        if (!ctrl)
+                                        {
+                                            // clear the list, set the states to
+                                            // default
+                                            foreach (DateTime item in Owner.SelectedDates)
+                                            {
+                                                Owner.RemovedItems.Add(item);
+                                            }
+                                            Owner.SelectedDates.ClearInternal();
+                                        }
+                                        Owner.HoverEnd = selectedDate;
+                                        Owner.HoverEndIndex = b.Index;
+                                        Owner.HighlightDays();
+                                    }
+                                    else
+                                    {
+                                        if (!ctrl)
+                                        {
+                                            // clear the list, set the states to
+                                            // default
+                                            foreach (DateTime item in Owner.SelectedDates)
+                                            {
+                                                Owner.RemovedItems.Add(item);
+                                            }
+                                            Owner.SelectedDates.ClearInternal();
+                                            Owner.UnHighlightDays();
+                                        }
+                                        Owner.HoverStart = selectedDate;
+                                        Owner.HoverStartIndex = b.Index;
+                                    }
+                                    return;
+                                }
+                        }
+                    }
+                    else
+                    {
+                        // If a click occurs on a BlackOutDay we set the
+                        // HoverStart to be null
+                        Owner.HoverStart = null;
+                    }
+                }
+                else
+                {
+                    _isControlPressed = false;
+                }
+            }
+        }
+        private void AddSelection(CalendarDayButton b)
+        {
+            if (Owner != null)
+            {
+                Owner.HoverEndIndex = b.Index;
+                Owner.HoverEnd = (DateTime)b.DataContext;
+
+                if (Owner.HoverEnd != null && Owner.HoverStart != null)
+                {
+                    // this is selection with Mouse, we do not guarantee the
+                    // range does not include BlackOutDates.  AddRange method
+                    // will throw away the BlackOutDates based on the
+                    // SelectionMode
+                    Owner.IsMouseSelection = true;
+                    Owner.SelectedDates.AddRange(Owner.HoverStart.Value, Owner.HoverEnd.Value);
+                    Owner.OnDayClick((DateTime)b.DataContext);
+                }
+            }
+        }
+        internal void Cell_MouseLeftButtonUp(object sender, PointerReleasedEventArgs e)
+        {
+            if (Owner != null)
+            {
+                CalendarDayButton b = sender as CalendarDayButton;
+                if (b != null && !b.IsBlackout)
+                {
+                    Owner.OnDayButtonMouseUp(e);
+                }
+                _isMouseLeftButtonDown = false;
+                if (b != null && b.DataContext != null)
+                {
+                    if (Owner.SelectionMode == CalendarSelectionMode.None || Owner.SelectionMode == CalendarSelectionMode.SingleDate)
+                    {
+                        Owner.OnDayClick((DateTime)b.DataContext);
+                        return;
+                    }
+                    if (Owner.HoverStart.HasValue)
+                    {
+                        switch (Owner.SelectionMode)
+                        {
+                            case CalendarSelectionMode.SingleRange:
+                                {
+                                    // Update SelectedDates
+                                    foreach (DateTime item in Owner.SelectedDates)
+                                    {
+                                        Owner.RemovedItems.Add(item);
+                                    }
+                                    Owner.SelectedDates.ClearInternal();
+                                    AddSelection(b);
+                                    return;
+                                }
+                            case CalendarSelectionMode.MultipleRange:
+                                {
+                                    // add the selection (either single day or
+                                    // SingleRange day)
+                                    AddSelection(b);
+                                    return;
+                                }
+                        }
+                    }
+                    else
+                    {
+                        // If the day is Disabled but a trailing day we should
+                        // be able to switch months
+                        if (b.IsInactive && b.IsBlackout)
+                        {
+                            Owner.OnDayClick((DateTime)b.DataContext);
+                        }
+                    }
+                }
+            }
+        }
+        private void Cell_Click(object sender, RoutedEventArgs e)
+        {
+            if (Owner != null)
+            {
+                if (_isControlPressed && Owner.SelectionMode == CalendarSelectionMode.MultipleRange)
+                {
+                    CalendarDayButton b = sender as CalendarDayButton;
+                    Debug.Assert(b != null, "The sender should be a non-null CalendarDayButton!");
+
+                    if (b.IsSelected)
+                    {
+                        Owner.HoverStart = null;
+                        _isMouseLeftButtonDown = false;
+                        b.IsSelected = false;
+                        if (b.DataContext != null)
+                        {
+                            Owner.SelectedDates.Remove((DateTime)b.DataContext);
+                        }
+                    }
+                }
+            }
+            _isControlPressed = false;
+        }
+
+        private void Month_CalendarButtonMouseDown(object sender, PointerPressedEventArgs e)
+        {
+            CalendarButton b = sender as CalendarButton;
+            Debug.Assert(b != null, "The sender should be a non-null CalendarDayButton!");
+
+            _isMouseLeftButtonDownYearView = true;
+
+            if (e != null)
+            {
+                _downEventArgYearView = e;
+            }
+
+            UpdateYearViewSelection(b);
+        }
+
+        internal void Month_CalendarButtonMouseUp(object sender, PointerReleasedEventArgs e)
+        {
+            _isMouseLeftButtonDownYearView = false;
+
+            if (Owner != null)
+            {
+                DateTime newmonth = (DateTime)((CalendarButton)sender).DataContext;
+
+                if (Owner.DisplayMode == CalendarMode.Year)
+                {
+                    Owner.DisplayDate = newmonth;
+                    Owner.DisplayMode = CalendarMode.Month;
+                }
+                else
+                {
+                    Debug.Assert(Owner.DisplayMode == CalendarMode.Decade, "The owning Calendar should be in decade mode!");
+                    Owner.SelectedMonth = newmonth;
+                    Owner.DisplayMode = CalendarMode.Year;
+                }
+            }
+        }
+
+        private void Month_MouseEnter(object sender, PointerEventArgs e)
+        {
+            if (_isMouseLeftButtonDownYearView)
+            {
+                CalendarButton b = sender as CalendarButton;
+                Debug.Assert(b != null, "The sender should be a non-null CalendarDayButton!");
+                UpdateYearViewSelection(b);
+            }
+        }
+
+        private void Month_MouseLeave(object sender, PointerEventArgs e)
+        {
+            if (_isMouseLeftButtonDownYearView)
+            {
+                CalendarButton b = sender as CalendarButton;
+                // The button is in Pressed state. Change the state to normal.
+                if (e.Device.Captured == b)
+                    e.Device.Capture(null);
+                //b.ReleaseMouseCapture();
+                if (_downEventArgYearView != null)
+                {
+                    var args =
+                        new PointerReleasedEventArgs()
+                        {
+                            Device = _downEventArgYearView.Device,
+                            MouseButton = _downEventArgYearView.MouseButton,
+                            Handled = _downEventArgYearView.Handled,
+                            InputModifiers = _downEventArgYearView.InputModifiers,
+                            Route = _downEventArgYearView.Route,
+                            Source = _downEventArgYearView.Source
+                        };
+
+                    b.SendMouseLeftButtonUp(args);
+                }
+                _lastCalendarButton = b;
+            }
+        }
+        private void MonthView_MouseLeave(object sender, PointerEventArgs e)
+        {
+            if (_lastCalendarDayButton != null)
+            {
+                e.Device.Capture(_lastCalendarDayButton);
+            }
+        }
+
+        private void YearView_MouseLeave(object sender, PointerEventArgs e)
+        {
+            if (_lastCalendarButton != null)
+            {
+                e.Device.Capture(_lastCalendarButton);
+            }
+        }
+        
+        internal void UpdateDisabled(bool isEnabled)
+        {
+            PseudoClasses.Set(":calendardisabled", !isEnabled);
+        }
+    }
+}
diff --git a/src/Avalonia.Controls/Calendar/DateTimeHelper.cs b/src/Avalonia.Controls/Calendar/DateTimeHelper.cs
new file mode 100644
index 0000000000..033bfc5726
--- /dev/null
+++ b/src/Avalonia.Controls/Calendar/DateTimeHelper.cs
@@ -0,0 +1,155 @@
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+
+using System;
+using System.Diagnostics;
+using System.Globalization;
+
+namespace Avalonia.Controls
+{
+    internal static class DateTimeHelper
+    {
+        public static DateTime? AddDays(DateTime time, int days)
+        {
+            System.Globalization.Calendar cal = new GregorianCalendar();
+            try
+            {
+                return cal.AddDays(time, days);
+            }
+            catch (ArgumentException)
+            {
+                return null;
+            }
+        }
+
+        public static DateTime? AddMonths(DateTime time, int months)
+        {
+            System.Globalization.Calendar cal = new GregorianCalendar();
+            try
+            {
+                return cal.AddMonths(time, months);
+            }
+            catch (ArgumentException)
+            {
+                return null;
+            }
+        }
+
+        public static DateTime? AddYears(DateTime time, int years)
+        {
+            System.Globalization.Calendar cal = new GregorianCalendar();
+            try
+            {
+                return cal.AddYears(time, years);
+            }
+            catch (ArgumentException)
+            {
+                return null;
+            }
+        }
+
+        public static int CompareDays(DateTime dt1, DateTime dt2)
+        {
+            return DateTime.Compare(DiscardTime(dt1).Value, DiscardTime(dt2).Value);
+        }
+
+        public static int CompareYearMonth(DateTime dt1, DateTime dt2)
+        {
+            return (dt1.Year - dt2.Year) * 12 + (dt1.Month - dt2.Month);
+        }
+
+        public static int DecadeOfDate(DateTime date)
+        {
+            return date.Year - (date.Year % 10);
+        }
+
+        public static DateTime DiscardDayTime(DateTime d)
+        {
+            int year = d.Year;
+            int month = d.Month;
+            DateTime newD = new DateTime(year, month, 1, 0, 0, 0);
+            return newD;
+        }
+
+        public static DateTime? DiscardTime(DateTime? d)
+        {
+            if (d == null)
+            {
+                return null;
+            }
+            return d.Value.Date;
+        }
+
+        public static int EndOfDecade(DateTime date)
+        {
+            return DecadeOfDate(date) + 9;
+        }
+
+        public static DateTimeFormatInfo GetCurrentDateFormat()
+        {
+            if (CultureInfo.CurrentCulture.Calendar is GregorianCalendar)
+            {
+                return CultureInfo.CurrentCulture.DateTimeFormat;
+            }
+            else
+            {
+                foreach (System.Globalization.Calendar cal in CultureInfo.CurrentCulture.OptionalCalendars)
+                {
+                    if (cal is GregorianCalendar)
+                    {
+                        // if the default calendar is not Gregorian, return the
+                        // first supported GregorianCalendar dtfi
+                        DateTimeFormatInfo dtfi = new CultureInfo(CultureInfo.CurrentCulture.Name).DateTimeFormat;
+                        dtfi.Calendar = cal;
+                        return dtfi;
+                    }
+                }
+
+                // if there are no GregorianCalendars in the OptionalCalendars
+                // list, use the invariant dtfi
+                DateTimeFormatInfo dt = new CultureInfo(CultureInfo.InvariantCulture.Name).DateTimeFormat;
+                dt.Calendar = new GregorianCalendar();
+                return dt;
+            }
+        }
+        public static bool InRange(DateTime date, CalendarDateRange range)
+        {
+            Debug.Assert(DateTime.Compare(range.Start, range.End) < 1, "The range should start before it ends!");
+
+            if (CompareDays(date, range.Start) > -1 && CompareDays(date, range.End) < 1)
+            {
+                return true;
+            }
+
+            return false;
+        }
+
+        public static string ToYearMonthPatternString(DateTime date)
+        {
+            string result = string.Empty;
+            DateTimeFormatInfo format = GetCurrentDateFormat();
+
+            if (format != null)
+            {
+                result = date.ToString(format.YearMonthPattern, format);
+            }
+
+            return result;
+        }
+
+        public static string ToYearString(DateTime date)
+        {
+            string result = string.Empty;
+            DateTimeFormatInfo format = GetCurrentDateFormat();
+
+            if (format != null)
+            {
+                result = date.Year.ToString(format);
+            }
+
+            return result;
+        }
+    }
+}
diff --git a/src/Avalonia.Controls/Calendar/SelectedDatesCollection.cs b/src/Avalonia.Controls/Calendar/SelectedDatesCollection.cs
new file mode 100644
index 0000000000..e6e0cf7c4f
--- /dev/null
+++ b/src/Avalonia.Controls/Calendar/SelectedDatesCollection.cs
@@ -0,0 +1,361 @@
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+
+using Avalonia.Threading;
+using System;
+using System.Collections.ObjectModel;
+using System.Threading;
+
+namespace Avalonia.Controls.Primitives
+{
+    public sealed class SelectedDatesCollection : ObservableCollection<DateTime>
+    {
+        /// <summary>
+        /// Inherited code: Requires comment.
+        /// </summary>
+        private Collection<DateTime> _addedItems;
+        
+        /// <summary>
+        /// Inherited code: Requires comment.
+        /// </summary>
+        private bool _isCleared;
+
+        /// <summary>
+        /// Inherited code: Requires comment.
+        /// </summary>
+        private bool _isRangeAdded;
+
+        /// <summary>
+        /// Inherited code: Requires comment.
+        /// </summary>
+        private Calendar _owner;
+
+        /// <summary>
+        /// Initializes a new instance of the
+        /// <see cref="T:Avalonia.Controls.Primitives.SelectedDatesCollection" />
+        /// class.
+        /// </summary>
+        /// <param name="owner">
+        /// The <see cref="T:Avalonia.Controls.Calendar" /> associated
+        /// with this object.
+        /// </param>
+        public SelectedDatesCollection(Calendar owner)
+        {
+            _owner = owner;
+            _addedItems = new Collection<DateTime>();
+        }
+
+        private void InvokeCollectionChanged(System.Collections.IList removedItems, System.Collections.IList addedItems)
+        {
+            _owner.OnSelectedDatesCollectionChanged(new SelectionChangedEventArgs(null, addedItems, removedItems));
+        }
+
+        /// <summary>
+        /// Adds all the dates in the specified range, which includes the first
+        /// and last dates, to the collection.
+        /// </summary>
+        /// <param name="start">The first date to add to the collection.</param>
+        /// <param name="end">The last date to add to the collection.</param>
+        public void AddRange(DateTime start, DateTime end)
+        {
+            DateTime? rangeStart;
+
+            // increment parameter specifies if the Days were selected in
+            // Descending order or Ascending order based on this value, we add 
+            // the days in the range either in Ascending order or in Descending
+            // order
+            int increment = (DateTime.Compare(end, start) >= 0) ? 1 : -1;
+
+            _addedItems.Clear();
+
+            rangeStart = start;
+            _isRangeAdded = true;
+
+            if (_owner.IsMouseSelection)
+            {
+                // In Mouse Selection we allow the user to be able to add
+                // multiple ranges in one action in MultipleRange Mode.  In
+                // SingleRange Mode, we only add the first selected range.
+                while (rangeStart.HasValue && DateTime.Compare(end, rangeStart.Value) != -increment)
+                {
+                    if (Calendar.IsValidDateSelection(_owner, rangeStart))
+                    {
+                        Add(rangeStart.Value);
+                    }
+                    else
+                    {
+                        if (_owner.SelectionMode == CalendarSelectionMode.SingleRange)
+                        {
+                            _owner.HoverEnd = rangeStart.Value.AddDays(-increment);
+                            break;
+                        }
+                    }
+
+                    rangeStart = DateTimeHelper.AddDays(rangeStart.Value, increment);
+                }
+            }
+            else
+            {
+                // If CalendarSelectionMode.SingleRange and a user
+                // programmatically tries to add multiple ranges, we will throw
+                // away the old range and replace it with the new one.  In order
+                // to provide the removed items without an additional event, we
+                // are calling ClearInternal
+                if (_owner.SelectionMode == CalendarSelectionMode.SingleRange && Count > 0)
+                {
+                    foreach (DateTime item in this)
+                    {
+                        _owner.RemovedItems.Add(item);
+                    }
+                    ClearInternal();
+                }
+
+                while (rangeStart.HasValue && DateTime.Compare(end, rangeStart.Value) != -increment)
+                {
+                    Add(rangeStart.Value);
+                    rangeStart = DateTimeHelper.AddDays(rangeStart.Value, increment);
+                }
+            }
+
+            _owner.OnSelectedDatesCollectionChanged(new SelectionChangedEventArgs(null, _addedItems, _owner.RemovedItems));
+            _owner.RemovedItems.Clear();
+            _owner.UpdateMonths();
+            _isRangeAdded = false;
+        }
+
+        /// <summary>
+        /// Removes all items from the collection.
+        /// </summary>
+        /// <remarks>
+        /// This implementation raises the CollectionChanged event.
+        /// </remarks>
+        protected override void ClearItems()
+        {
+            EnsureValidThread();
+
+            Collection<DateTime> addedItems = new Collection<DateTime>();
+            Collection<DateTime> removedItems = new Collection<DateTime>();
+
+            foreach (DateTime item in this)
+            {
+                removedItems.Add(item);
+            }
+
+            base.ClearItems();
+
+            // The event fires after SelectedDate changes
+            if (_owner.SelectionMode != CalendarSelectionMode.None && _owner.SelectedDate != null)
+            {
+                _owner.SelectedDate = null;
+            }
+
+            if (removedItems.Count != 0)
+            {
+                InvokeCollectionChanged(removedItems, addedItems);
+            }
+            _owner.UpdateMonths();
+        }
+
+        /// <summary>
+        /// Inserts an item into the collection at the specified index.
+        /// </summary>
+        /// <param name="index">
+        /// The zero-based index at which item should be inserted.
+        /// </param>
+        /// <param name="item">The object to insert.</param>
+        /// <remarks>
+        /// This implementation raises the CollectionChanged event.
+        /// </remarks>
+        protected override void InsertItem(int index, DateTime item)
+        {
+            EnsureValidThread();
+
+            if (!Contains(item))
+            {
+                Collection<DateTime> addedItems = new Collection<DateTime>();
+
+                if (CheckSelectionMode())
+                {
+                    if (Calendar.IsValidDateSelection(_owner, item))
+                    {
+                        // If the Collection is cleared since it is SingleRange
+                        // and it had another range set the index to 0
+                        if (_isCleared)
+                        {
+                            index = 0;
+                            _isCleared = false;
+                        }
+
+                        base.InsertItem(index, item);
+
+                        // The event fires after SelectedDate changes
+                        if (index == 0 && !(_owner.SelectedDate.HasValue && DateTime.Compare(_owner.SelectedDate.Value, item) == 0))
+                        {
+                            _owner.SelectedDate = item;
+                        }
+
+                        if (!_isRangeAdded)
+                        {
+                            addedItems.Add(item);
+
+                            InvokeCollectionChanged(_owner.RemovedItems, addedItems);
+                            _owner.RemovedItems.Clear();
+                            int monthDifference = DateTimeHelper.CompareYearMonth(item, _owner.DisplayDateInternal);
+
+                            if (monthDifference < 2 && monthDifference > -2)
+                            {
+                                _owner.UpdateMonths();
+                            }
+                        }
+                        else
+                        {
+                            _addedItems.Add(item);
+                        }
+                    }
+                    else
+                    {
+                        throw new ArgumentOutOfRangeException("SelectedDate value is not valid.");
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Removes the item at the specified index of the collection.
+        /// </summary>
+        /// <param name="index">
+        /// The zero-based index of the element to remove.
+        /// </param>
+        /// <remarks>
+        /// This implementation raises the CollectionChanged event.
+        /// </remarks>
+        protected override void RemoveItem(int index)
+        {
+            EnsureValidThread();
+
+            if (index >= Count)
+            {
+                base.RemoveItem(index);
+            }
+            else
+            {
+                Collection<DateTime> addedItems = new Collection<DateTime>();
+                Collection<DateTime> removedItems = new Collection<DateTime>();
+                int monthDifference = DateTimeHelper.CompareYearMonth(this[index], _owner.DisplayDateInternal);
+
+                removedItems.Add(this[index]);
+                base.RemoveItem(index);
+
+                // The event fires after SelectedDate changes
+                if (index == 0)
+                {
+                    if (Count > 0)
+                    {
+                        _owner.SelectedDate = this[0];
+                    }
+                    else
+                    {
+                        _owner.SelectedDate = null;
+                    }
+                }
+
+                InvokeCollectionChanged(removedItems, addedItems);
+
+                if (monthDifference < 2 && monthDifference > -2)
+                {
+                    _owner.UpdateMonths();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Replaces the element at the specified index.
+        /// </summary>
+        /// <param name="index">
+        /// The zero-based index of the element to replace.
+        /// </param>
+        /// <param name="item">
+        /// The new value for the element at the specified index.
+        /// </param>
+        /// <remarks>
+        /// This implementation raises the CollectionChanged event.
+        /// </remarks>
+        protected override void SetItem(int index, DateTime item)
+        {
+            EnsureValidThread();
+
+            if (!Contains(item))
+            {
+                Collection<DateTime> addedItems = new Collection<DateTime>();
+                Collection<DateTime> removedItems = new Collection<DateTime>();
+
+                if (index >= Count)
+                {
+                    base.SetItem(index, item);
+                }
+                else
+                {
+                    if (item != null && DateTime.Compare(this[index], item) != 0 && Calendar.IsValidDateSelection(_owner, item))
+                    {
+                        removedItems.Add(this[index]);
+                        base.SetItem(index, item);
+                        addedItems.Add(item);
+
+                        // The event fires after SelectedDate changes
+                        if (index == 0 && !(_owner.SelectedDate.HasValue && DateTime.Compare(_owner.SelectedDate.Value, item) == 0))
+                        {
+                            _owner.SelectedDate = item;
+                        }
+                        InvokeCollectionChanged(removedItems, addedItems);
+
+                        int monthDifference = DateTimeHelper.CompareYearMonth(item, _owner.DisplayDateInternal);
+
+                        if (monthDifference < 2 && monthDifference > -2)
+                        {
+                            _owner.UpdateMonths();
+                        }
+                    }
+                }
+            }
+        }
+        
+        internal void ClearInternal()
+        {
+            base.ClearItems();
+        }
+        
+        private bool CheckSelectionMode()
+        {
+            if (_owner.SelectionMode == CalendarSelectionMode.None)
+            {
+                throw new InvalidOperationException("The SelectedDate property cannot be set when the selection mode is None.");
+            }
+            if (_owner.SelectionMode == CalendarSelectionMode.SingleDate && Count > 0)
+            {
+                throw new InvalidOperationException("The SelectedDates collection can be changed only in a multiple selection mode. Use the SelectedDate in a single selection mode.");
+            }
+
+            // if user tries to add an item into the SelectedDates in
+            // SingleRange mode, we throw away the old range and replace it with
+            // the new one in order to provide the removed items without an
+            // additional event, we are calling ClearInternal
+            if (_owner.SelectionMode == CalendarSelectionMode.SingleRange && !_isRangeAdded && Count > 0)
+            {
+                foreach (DateTime item in this)
+                {
+                    _owner.RemovedItems.Add(item);
+                }
+                ClearInternal();
+                _isCleared = true;
+            }
+            return true;
+        }
+        
+        private void EnsureValidThread()
+        {
+            Dispatcher.UIThread.VerifyAccess();
+        }
+    }
+}
diff --git a/src/Avalonia.Controls/Classes.cs b/src/Avalonia.Controls/Classes.cs
index c897e86697..613273d5c7 100644
--- a/src/Avalonia.Controls/Classes.cs
+++ b/src/Avalonia.Controls/Classes.cs
@@ -179,7 +179,7 @@ namespace Avalonia.Controls
             {
                 ThrowIfPseudoclass(name, "removed");
 
-                if (!Contains(name))
+                if (Contains(name))
                 {
                     c.Add(name);
                 }
diff --git a/src/Avalonia.Controls/ContentControl.cs b/src/Avalonia.Controls/ContentControl.cs
index 0eba3c13ae..6da6da54a5 100644
--- a/src/Avalonia.Controls/ContentControl.cs
+++ b/src/Avalonia.Controls/ContentControl.cs
@@ -51,6 +51,7 @@ namespace Avalonia.Controls
         /// Gets or sets the content to display.
         /// </summary>
         [Content]
+        [DependsOn(nameof(ContentTemplate))]
         public object Content
         {
             get { return GetValue(ContentProperty); }
diff --git a/src/Avalonia.Controls/Control.cs b/src/Avalonia.Controls/Control.cs
index d4777b2f8a..89721e2e05 100644
--- a/src/Avalonia.Controls/Control.cs
+++ b/src/Avalonia.Controls/Control.cs
@@ -487,11 +487,6 @@ namespace Avalonia.Controls
         void ILogical.NotifyResourcesChanged(ResourcesChangedEventArgs e)
         {
             ResourcesChanged?.Invoke(this, new ResourcesChangedEventArgs());
-
-            foreach (var child in LogicalChildren)
-            {
-                child.NotifyResourcesChanged(e);
-            }
         }
 
         /// <inheritdoc/>
@@ -536,6 +531,15 @@ namespace Avalonia.Controls
                 }
 
                 _parent = (IControl)parent;
+
+                if (old != null)
+                {
+                    old.ResourcesChanged -= ThisResourcesChanged; 
+                }
+                if (_parent != null)
+                {
+                    _parent.ResourcesChanged += ThisResourcesChanged; 
+                }
                 ((ILogical)this).NotifyResourcesChanged(new ResourcesChangedEventArgs());
 
                 if (_parent is IStyleRoot || _parent?.IsAttachedToLogicalTree == true || this is IStyleRoot)
@@ -621,7 +625,6 @@ namespace Avalonia.Controls
             Contract.Requires<ArgumentNullException>(property != null);
             Contract.Requires<ArgumentNullException>(selector != null);
             Contract.Requires<ArgumentNullException>(className != null);
-            Contract.Requires<ArgumentNullException>(property != null);
 
             if (string.IsNullOrWhiteSpace(className))
             {
diff --git a/src/Avalonia.Controls/DropDown.cs b/src/Avalonia.Controls/DropDown.cs
index fa2e0c1e16..6b27c479ba 100644
--- a/src/Avalonia.Controls/DropDown.cs
+++ b/src/Avalonia.Controls/DropDown.cs
@@ -96,6 +96,16 @@ namespace Avalonia.Controls
             this.UpdateSelectionBoxItem(this.SelectedItem);
         }
 
+        protected override void OnGotFocus(GotFocusEventArgs e)
+        {
+            base.OnGotFocus(e);
+
+            if (!e.Handled && e.NavigationMethod == NavigationMethod.Directional)
+            {
+                e.Handled = UpdateSelectionFromEventSource(e.Source);
+            }
+        }
+
         /// <inheritdoc/>
         protected override void OnKeyDown(KeyEventArgs e)
         {
@@ -104,7 +114,7 @@ namespace Avalonia.Controls
             if (!e.Handled)
             {
                 if (e.Key == Key.F4 ||
-                    (e.Key == Key.Down && ((e.Modifiers & InputModifiers.Alt) != 0)))
+                    ((e.Key == Key.Down || e.Key == Key.Up) && ((e.Modifiers & InputModifiers.Alt) != 0)))
                 {
                     IsDropDownOpen = !IsDropDownOpen;
                     e.Handled = true;
@@ -114,6 +124,27 @@ namespace Avalonia.Controls
                     IsDropDownOpen = false;
                     e.Handled = true;
                 }
+
+                if (!IsDropDownOpen)
+                {
+                    if (e.Key == Key.Down)
+                    {
+                        if (SelectedIndex == -1)
+                            SelectedIndex = 0;
+                        
+                        if (++SelectedIndex >= ItemCount)
+                            SelectedIndex = 0;
+                        
+                        e.Handled = true;
+                    }
+                    else if (e.Key == Key.Up)
+                    {
+                        if (--SelectedIndex < 0)
+                            SelectedIndex = ItemCount - 1;
+                        
+                        e.Handled = true;
+                    }
+                }
             }
         }
 
diff --git a/src/Avalonia.Controls/IPanel.cs b/src/Avalonia.Controls/IPanel.cs
index 5bcfd33e86..ce2c63ffc8 100644
--- a/src/Avalonia.Controls/IPanel.cs
+++ b/src/Avalonia.Controls/IPanel.cs
@@ -9,8 +9,8 @@ namespace Avalonia.Controls
     public interface IPanel : IControl
     {
         /// <summary>
-        /// Gets or sets the children of the <see cref="Panel"/>.
+        /// Gets the children of the <see cref="Panel"/>.
         /// </summary>
-        Controls Children { get; set; }
+        Controls Children { get; }
     }
 }
\ No newline at end of file
diff --git a/src/Avalonia.Controls/ItemsControl.cs b/src/Avalonia.Controls/ItemsControl.cs
index aa209e0462..4366de1cd6 100644
--- a/src/Avalonia.Controls/ItemsControl.cs
+++ b/src/Avalonia.Controls/ItemsControl.cs
@@ -11,6 +11,7 @@ using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
 using Avalonia.Controls.Utils;
+using Avalonia.Input;
 using Avalonia.LogicalTree;
 using Avalonia.Metadata;
 
@@ -106,6 +107,12 @@ namespace Avalonia.Controls
             set { SetAndRaise(ItemsProperty, ref _items, value); }
         }
 
+        public int ItemCount
+        {
+            get;
+            private set;
+        }
+
         /// <summary>
         /// Gets or sets the panel used to display the items.
         /// </summary>
@@ -352,6 +359,10 @@ namespace Avalonia.Controls
                     RemoveControlItemsFromLogicalChildren(e.OldItems);
                     break;
             }
+            
+            int? count = (Items as IList)?.Count;
+            if (count != null)
+                ItemCount = (int)count;
 
             var collection = sender as ICollection;
             PseudoClasses.Set(":empty", collection == null || collection.Count == 0);
diff --git a/src/Avalonia.Controls/Panel.cs b/src/Avalonia.Controls/Panel.cs
index 3272d3779b..a2cb013300 100644
--- a/src/Avalonia.Controls/Panel.cs
+++ b/src/Avalonia.Controls/Panel.cs
@@ -25,8 +25,6 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<IBrush> BackgroundProperty =
             Border.BackgroundProperty.AddOwner<Panel>();
 
-        private readonly Controls _children = new Controls();
-
         /// <summary>
         /// Initializes static members of the <see cref="Panel"/> class.
         /// </summary>
@@ -40,38 +38,14 @@ namespace Avalonia.Controls
         /// </summary>
         public Panel()
         {
-            _children.CollectionChanged += ChildrenChanged;
+            Children.CollectionChanged += ChildrenChanged;
         }
 
         /// <summary>
-        /// Gets or sets the children of the <see cref="Panel"/>.
+        /// Gets the children of the <see cref="Panel"/>.
         /// </summary>
-        /// <remarks>
-        /// Even though this property can be set, the setter is only intended for use in object
-        /// initializers. Assigning to this property does not change the underlying collection,
-        /// it simply clears the existing collection and adds the contents of the assigned
-        /// collection.
-        /// </remarks>
         [Content]
-        public Controls Children
-        {
-            get
-            {
-                return _children;
-            }
-
-            set
-            {
-                Contract.Requires<ArgumentNullException>(value != null);
-
-                if (_children != value)
-                {
-                    VisualChildren.Clear();
-                    _children.Clear();
-                    _children.AddRange(value);
-                }
-            }
-        }
+        public Controls Children { get; } = new Controls();
 
         /// <summary>
         /// Gets or Sets Panel background brush.
@@ -115,6 +89,11 @@ namespace Avalonia.Controls
                     VisualChildren.AddRange(e.NewItems.OfType<Visual>());
                     break;
 
+                case NotifyCollectionChangedAction.Move:
+                    LogicalChildren.MoveRange(e.OldStartingIndex, e.OldItems.Count, e.NewStartingIndex);
+                    VisualChildren.MoveRange(e.OldStartingIndex, e.OldItems.Count, e.NewStartingIndex);
+                    break;
+
                 case NotifyCollectionChangedAction.Remove:
                     controls = e.OldItems.OfType<Control>().ToList();
                     LogicalChildren.RemoveAll(controls);
@@ -132,11 +111,7 @@ namespace Avalonia.Controls
                     break;
 
                 case NotifyCollectionChangedAction.Reset:
-                    controls = e.OldItems.OfType<Control>().ToList();
-                    LogicalChildren.Clear();
-                    VisualChildren.Clear();
-                    VisualChildren.AddRange(_children);
-                    break;
+                    throw new NotSupportedException();
             }
 
             InvalidateMeasure();
diff --git a/src/Avalonia.Controls/Presenters/ContentPresenter.cs b/src/Avalonia.Controls/Presenters/ContentPresenter.cs
index c1adff402a..a97fdf8784 100644
--- a/src/Avalonia.Controls/Presenters/ContentPresenter.cs
+++ b/src/Avalonia.Controls/Presenters/ContentPresenter.cs
@@ -8,6 +8,7 @@ using Avalonia.Controls.Templates;
 using Avalonia.Layout;
 using Avalonia.LogicalTree;
 using Avalonia.Media;
+using Avalonia.Metadata;
 using Avalonia.VisualTree;
 
 namespace Avalonia.Controls.Presenters
@@ -139,6 +140,7 @@ namespace Avalonia.Controls.Presenters
         /// <summary>
         /// Gets or sets the content to be displayed by the presenter.
         /// </summary>
+        [DependsOn(nameof(ContentTemplate))]
         public object Content
         {
             get { return GetValue(ContentProperty); }
@@ -255,18 +257,9 @@ namespace Avalonia.Controls.Presenters
                     LogicalChildren.Remove(oldChild);
                 }
 
-                if (newChild.Parent == null)
+                if (newChild.Parent == null && TemplatedParent == null)
                 {
-                    var templatedLogicalParent = TemplatedParent as ILogical;
-
-                    if (templatedLogicalParent != null)
-                    {
-                        ((ISetLogicalParent)newChild).SetParent(templatedLogicalParent);
-                    }
-                    else
-                    {
-                        LogicalChildren.Add(newChild);
-                    }
+                    LogicalChildren.Add(newChild);
                 }
 
                 VisualChildren.Add(newChild);
diff --git a/src/Avalonia.Controls/Primitives/PopupRoot.cs b/src/Avalonia.Controls/Primitives/PopupRoot.cs
index a999e4ae37..507a085fed 100644
--- a/src/Avalonia.Controls/Primitives/PopupRoot.cs
+++ b/src/Avalonia.Controls/Primitives/PopupRoot.cs
@@ -8,6 +8,7 @@ using Avalonia.Interactivity;
 using Avalonia.Layout;
 using Avalonia.Media;
 using Avalonia.Platform;
+using Avalonia.Styling;
 using Avalonia.VisualTree;
 using JetBrains.Annotations;
 
@@ -16,7 +17,7 @@ namespace Avalonia.Controls.Primitives
     /// <summary>
     /// The root window of a <see cref="Popup"/>.
     /// </summary>
-    public class PopupRoot : WindowBase, IInteractive, IHostedVisualTreeRoot, IDisposable
+    public class PopupRoot : WindowBase, IInteractive, IHostedVisualTreeRoot, IDisposable, IStyleHost
     {
         private IDisposable _presenterSubscription;
 
@@ -66,6 +67,11 @@ namespace Avalonia.Controls.Primitives
         /// </summary>
         IVisual IHostedVisualTreeRoot.Host => Parent;
 
+        /// <summary>
+        /// Gets the styling parent of the popup root.
+        /// </summary>
+        IStyleHost IStyleHost.StylingParent => Parent;
+
         /// <inheritdoc/>
         public void Dispose() => PlatformImpl?.Dispose();
 
@@ -90,20 +96,23 @@ namespace Avalonia.Controls.Primitives
 
         private void SetTemplatedParentAndApplyChildTemplates(IControl control)
         {
-            var templatedParent = Parent.TemplatedParent;
-
-            if (control.TemplatedParent == null)
+            if (control != null)
             {
-                control.SetValue(TemplatedParentProperty, templatedParent);
-            }
+                var templatedParent = Parent.TemplatedParent;
 
-            control.ApplyTemplate();
+                if (control.TemplatedParent == null)
+                {
+                    control.SetValue(TemplatedParentProperty, templatedParent);
+                }
 
-            if (!(control is IPresenter) && control.TemplatedParent == templatedParent)
-            {
-                foreach (IControl child in control.GetVisualChildren())
+                control.ApplyTemplate();
+
+                if (!(control is IPresenter) && control.TemplatedParent == templatedParent)
                 {
-                    SetTemplatedParentAndApplyChildTemplates(child);
+                    foreach (IControl child in control.GetVisualChildren())
+                    {
+                        SetTemplatedParentAndApplyChildTemplates(child);
+                    }
                 }
             }
         }
diff --git a/src/Avalonia.Controls/Primitives/RangeBase.cs b/src/Avalonia.Controls/Primitives/RangeBase.cs
index b69dbba637..b46562e99e 100644
--- a/src/Avalonia.Controls/Primitives/RangeBase.cs
+++ b/src/Avalonia.Controls/Primitives/RangeBase.cs
@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using Avalonia.Data;
 using Avalonia.Utilities;
 
 namespace Avalonia.Controls.Primitives
@@ -36,7 +37,8 @@ namespace Avalonia.Controls.Primitives
             AvaloniaProperty.RegisterDirect<RangeBase, double>(
                 nameof(Value),
                 o => o.Value,
-                (o, v) => o.Value = v);
+                (o, v) => o.Value = v,
+                defaultBindingMode: BindingMode.TwoWay);
 
         /// <summary>
         /// Defines the <see cref="SmallChange"/> property.
diff --git a/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs b/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
index ab09a4701d..2e668fda95 100644
--- a/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
+++ b/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
@@ -151,15 +151,23 @@ namespace Avalonia.Controls.Primitives
             {
                 if (_updateCount == 0)
                 {
-                    var old = SelectedIndex;
-                    var effective = (value >= 0 && value < Items?.Cast<object>().Count()) ? value : -1;
-
-                    if (old != effective)
+                    SetAndRaise(SelectedIndexProperty, ref _selectedIndex, (int val, ref int backing, Action<Action> notifyWrapper) =>
                     {
-                        _selectedIndex = effective;
-                        RaisePropertyChanged(SelectedIndexProperty, old, effective, BindingPriority.LocalValue);
-                        SelectedItem = ElementAt(Items, effective);
-                    }
+                        var old = backing;
+                        var effective = (val >= 0 && val < Items?.Cast<object>().Count()) ? val : -1;
+
+                        if (old != effective)
+                        {
+                            backing = effective;
+                            notifyWrapper(() =>
+                                RaisePropertyChanged(
+                                    SelectedIndexProperty,
+                                    old,
+                                    effective,
+                                    BindingPriority.LocalValue));
+                            SelectedItem = ElementAt(Items, effective);
+                        }
+                    }, value);
                 }
                 else
                 {
@@ -183,31 +191,41 @@ namespace Avalonia.Controls.Primitives
             {
                 if (_updateCount == 0)
                 {
-                    var old = SelectedItem;
-                    var index = IndexOf(Items, value);
-                    var effective = index != -1 ? value : null;
-
-                    if (!object.Equals(effective, old))
+                    SetAndRaise(SelectedItemProperty, ref _selectedItem, (object val, ref object backing, Action<Action> notifyWrapper) =>
                     {
-                        _selectedItem = effective;
-                        RaisePropertyChanged(SelectedItemProperty, old, effective, BindingPriority.LocalValue);
-                        SelectedIndex = index;
+                        var old = backing;
+                        var index = IndexOf(Items, val);
+                        var effective = index != -1 ? val : null;
 
-                        if (effective != null)
+                        if (!object.Equals(effective, old))
                         {
-                            if (SelectedItems.Count != 1 || SelectedItems[0] != effective)
+                            backing = effective;
+
+                            notifyWrapper(() =>
+                                RaisePropertyChanged(
+                                    SelectedItemProperty,
+                                    old,
+                                    effective,
+                                    BindingPriority.LocalValue));
+
+                            SelectedIndex = index;
+
+                            if (effective != null)
+                            {
+                                if (SelectedItems.Count != 1 || SelectedItems[0] != effective)
+                                {
+                                    _syncingSelectedItems = true;
+                                    SelectedItems.Clear();
+                                    SelectedItems.Add(effective);
+                                    _syncingSelectedItems = false;
+                                }
+                            }
+                            else if (SelectedItems.Count > 0)
                             {
-                                _syncingSelectedItems = true;
                                 SelectedItems.Clear();
-                                SelectedItems.Add(effective);
-                                _syncingSelectedItems = false;
                             }
                         }
-                        else if (SelectedItems.Count > 0)
-                        {
-                            SelectedItems.Clear();
-                        }
-                    }
+                    }, value);
                 }
                 else
                 {
@@ -297,7 +315,7 @@ namespace Avalonia.Controls.Primitives
                 .OfType<IControl>()
                 .FirstOrDefault(x => x.LogicalParent == this && ItemContainerGenerator?.IndexFromContainer(x) != -1);
 
-            return item as IControl;
+            return item;
         }
 
         /// <inheritdoc/>
diff --git a/src/Avalonia.Controls/Primitives/ToggleButton.cs b/src/Avalonia.Controls/Primitives/ToggleButton.cs
index 4e9e326997..7d500975f0 100644
--- a/src/Avalonia.Controls/Primitives/ToggleButton.cs
+++ b/src/Avalonia.Controls/Primitives/ToggleButton.cs
@@ -9,26 +9,37 @@ namespace Avalonia.Controls.Primitives
 {
     public class ToggleButton : Button
     {
-        public static readonly DirectProperty<ToggleButton, bool> IsCheckedProperty =
-            AvaloniaProperty.RegisterDirect<ToggleButton, bool>(
-                "IsChecked",
+        public static readonly DirectProperty<ToggleButton, bool?> IsCheckedProperty =
+            AvaloniaProperty.RegisterDirect<ToggleButton, bool?>(
+                nameof(IsChecked),
                 o => o.IsChecked,
-                (o,v) => o.IsChecked = v,
+                (o, v) => o.IsChecked = v,
                 defaultBindingMode: BindingMode.TwoWay);
 
-        private bool _isChecked;
+        public static readonly StyledProperty<bool> IsThreeStateProperty =
+            AvaloniaProperty.Register<ToggleButton, bool>(nameof(IsThreeState));
+
+        private bool? _isChecked = false;
 
         static ToggleButton()
         {
-            PseudoClass(IsCheckedProperty, ":checked");
+            PseudoClass(IsCheckedProperty, c => c == true, ":checked");
+            PseudoClass(IsCheckedProperty, c => c == false, ":unchecked");
+            PseudoClass(IsCheckedProperty, c => c == null, ":indeterminate");
         }
 
-        public bool IsChecked
+        public bool? IsChecked
         {
             get { return _isChecked; }
             set { SetAndRaise(IsCheckedProperty, ref _isChecked, value); }
         }
 
+        public bool IsThreeState
+        {
+            get => GetValue(IsThreeStateProperty);
+            set => SetValue(IsThreeStateProperty, value);
+        }
+
         protected override void OnClick()
         {
             Toggle();
@@ -37,7 +48,16 @@ namespace Avalonia.Controls.Primitives
 
         protected virtual void Toggle()
         {
-            IsChecked = !IsChecked;
+            if (IsChecked.HasValue)
+                if (IsChecked.Value)
+                    if (IsThreeState)
+                        IsChecked = null;
+                    else
+                        IsChecked = false;
+                else
+                    IsChecked = true;
+            else
+                IsChecked = false;
         }
     }
 }
diff --git a/src/Avalonia.Controls/Primitives/Track.cs b/src/Avalonia.Controls/Primitives/Track.cs
index 8c577665d5..648fe5f4b0 100644
--- a/src/Avalonia.Controls/Primitives/Track.cs
+++ b/src/Avalonia.Controls/Primitives/Track.cs
@@ -154,7 +154,11 @@ namespace Avalonia.Controls.Primitives
 
                 if (increaseButton != null)
                 {
-                    increaseButton.Arrange(new Rect(firstWidth + thumbWidth, 0, remaining - firstWidth, finalSize.Height));
+                    increaseButton.Arrange(new Rect(
+                        firstWidth + thumbWidth,
+                        0,
+                        Math.Max(0, remaining - firstWidth),
+                        finalSize.Height));
                 }
             }
             else
@@ -185,7 +189,11 @@ namespace Avalonia.Controls.Primitives
 
                 if (increaseButton != null)
                 {
-                    increaseButton.Arrange(new Rect(0, firstHeight + thumbHeight, finalSize.Width, Math.Max(remaining - firstHeight, 0)));
+                    increaseButton.Arrange(new Rect(
+                        0,
+                        firstHeight + thumbHeight,
+                        finalSize.Width,
+                        Math.Max(remaining - firstHeight, 0)));
                 }
             }
 
diff --git a/src/Avalonia.Controls/ProgressBar.cs b/src/Avalonia.Controls/ProgressBar.cs
index 0ff3a78c1f..8cf6b149cb 100644
--- a/src/Avalonia.Controls/ProgressBar.cs
+++ b/src/Avalonia.Controls/ProgressBar.cs
@@ -28,9 +28,6 @@ namespace Avalonia.Controls
         {
             ValueProperty.Changed.AddClassHandler<ProgressBar>(x => x.ValueChanged);
 
-            HorizontalAlignmentProperty.OverrideDefaultValue<ProgressBar>(HorizontalAlignment.Left);
-            VerticalAlignmentProperty.OverrideDefaultValue<ProgressBar>(VerticalAlignment.Top);
-
             IsIndeterminateProperty.Changed.AddClassHandler<ProgressBar>(
                 (p, e) => { if (p._indicator != null) p.UpdateIsIndeterminate((bool)e.NewValue); });
             OrientationProperty.Changed.AddClassHandler<ProgressBar>(
@@ -112,8 +109,10 @@ namespace Avalonia.Controls
         private void UpdateIsIndeterminate(bool isIndeterminate)
         {
             if (isIndeterminate)
+            {
                 if (_indeterminateAnimation == null || _indeterminateAnimation.Disposed)
                     _indeterminateAnimation = IndeterminateAnimation.StartAnimation(this);
+            }
             else
                 _indeterminateAnimation?.Dispose();
         }
diff --git a/src/Avalonia.Controls/RadioButton.cs b/src/Avalonia.Controls/RadioButton.cs
index 25ab0f9c12..945335b8f7 100644
--- a/src/Avalonia.Controls/RadioButton.cs
+++ b/src/Avalonia.Controls/RadioButton.cs
@@ -17,17 +17,17 @@ namespace Avalonia.Controls
 
         protected override void Toggle()
         {
-            if (!IsChecked)
+            if (!IsChecked.GetValueOrDefault())
             {
                 IsChecked = true;
             }
         }
 
-        private void IsCheckedChanged(bool value)
+        private void IsCheckedChanged(bool? value)
         {
             var parent = this.GetVisualParent();
 
-            if (value && parent != null)
+            if (value.GetValueOrDefault() && parent != null)
             {
                 var siblings = parent
                     .GetVisualChildren()
@@ -36,7 +36,8 @@ namespace Avalonia.Controls
 
                 foreach (var sibling in siblings)
                 {
-                    sibling.IsChecked = false;
+                    if (sibling.IsChecked.GetValueOrDefault())
+                        sibling.IsChecked = false;
                 }
             }
         }
diff --git a/src/Avalonia.Controls/TextBox.cs b/src/Avalonia.Controls/TextBox.cs
index 92ab12f82e..36ef8d05c3 100644
--- a/src/Avalonia.Controls/TextBox.cs
+++ b/src/Avalonia.Controls/TextBox.cs
@@ -97,6 +97,7 @@ namespace Avalonia.Controls
         private UndoRedoHelper<UndoRedoState> _undoRedoHelper;
         private bool _ignoreTextChanges;
         private IEnumerable<Exception> _dataValidationErrors;
+        private static readonly string[] invalidCharacters = new String[1]{"\u007f"};
 
         static TextBox()
         {
@@ -177,6 +178,10 @@ namespace Avalonia.Controls
             {
                 value = CoerceCaretIndex(value);
                 SetAndRaise(SelectionStartProperty, ref _selectionStart, value);
+                if (SelectionStart == SelectionEnd)
+                {
+                    CaretIndex = SelectionStart;
+                }
             }
         }
 
@@ -191,6 +196,10 @@ namespace Avalonia.Controls
             {
                 value = CoerceCaretIndex(value);
                 SetAndRaise(SelectionEndProperty, ref _selectionEnd, value);
+                if (SelectionStart == SelectionEnd)
+                {
+                    CaretIndex = SelectionEnd;
+                }
             }
         }
 
@@ -280,6 +289,7 @@ namespace Avalonia.Controls
         {
             if (!IsReadOnly)
             {
+                input = RemoveInvalidCharacters(input);
                 string text = Text ?? string.Empty;
                 int caretIndex = CaretIndex;
                 if (!string.IsNullOrEmpty(input))
@@ -295,6 +305,16 @@ namespace Avalonia.Controls
             }
         }
 
+        public string RemoveInvalidCharacters(string text)
+        {
+            for (var i = 0; i < invalidCharacters.Length; i++)
+            {
+                text = text.Replace(invalidCharacters[i], string.Empty);
+            }
+
+            return text;
+        }
+
         private async void Copy()
         {
             await ((IClipboard)AvaloniaLocator.Current.GetService(typeof(IClipboard)))
diff --git a/src/Avalonia.Controls/TreeView.cs b/src/Avalonia.Controls/TreeView.cs
index 079e571d29..fa3ecdedef 100644
--- a/src/Avalonia.Controls/TreeView.cs
+++ b/src/Avalonia.Controls/TreeView.cs
@@ -176,10 +176,7 @@ namespace Avalonia.Controls
 
                 SelectedItem = item;
 
-                if (SelectedItem != null)
-                {
-                    MarkContainerSelected(container, true);
-                }
+                MarkContainerSelected(container, true);
             }
         }
 
diff --git a/src/Avalonia.Controls/VirtualizingStackPanel.cs b/src/Avalonia.Controls/VirtualizingStackPanel.cs
index 834f6d218b..409dd231ad 100644
--- a/src/Avalonia.Controls/VirtualizingStackPanel.cs
+++ b/src/Avalonia.Controls/VirtualizingStackPanel.cs
@@ -134,12 +134,14 @@ namespace Avalonia.Controls
 
         protected override IInputElement GetControlInDirection(NavigationDirection direction, IControl from)
         {
+            if (from == null)
+                return null;
+
             var logicalScrollable = Parent as ILogicalScrollable;
-            var fromControl = from as IControl;
 
-            if (logicalScrollable?.IsLogicalScrollEnabled == true && fromControl != null)
+            if (logicalScrollable?.IsLogicalScrollEnabled == true)
             {
-                return logicalScrollable.GetControlInDirection(direction, fromControl);
+                return logicalScrollable.GetControlInDirection(direction, from);
             }
             else
             {
diff --git a/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj b/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj
index abbdd15bed..5f8e25269b 100644
--- a/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj
+++ b/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj
@@ -11,7 +11,7 @@
     <DefineConstants>TRACE;DEBUG</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Diagnostics.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Diagnostics.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
@@ -21,7 +21,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Diagnostics.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Diagnostics.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
diff --git a/src/Avalonia.Diagnostics/Views/TreePage.xaml.cs b/src/Avalonia.Diagnostics/Views/TreePage.xaml.cs
index 7e4e5a8564..d445f1cd70 100644
--- a/src/Avalonia.Diagnostics/Views/TreePage.xaml.cs
+++ b/src/Avalonia.Diagnostics/Views/TreePage.xaml.cs
@@ -27,6 +27,12 @@ namespace Avalonia.Diagnostics.Views
 
             if (layer != null)
             {
+                if (_adorner != null)
+                {
+                    ((Panel)_adorner.Parent).Children.Remove(_adorner);
+                    _adorner = null;
+                }
+
                 _adorner = new Rectangle
                 {
                     Fill = new SolidColorBrush(0x80a0c5e8),
diff --git a/src/Avalonia.DotNetCoreRuntime/Avalonia.DotNetCoreRuntime.csproj b/src/Avalonia.DotNetCoreRuntime/Avalonia.DotNetCoreRuntime.csproj
index 53b2c997d0..8630e7b228 100644
--- a/src/Avalonia.DotNetCoreRuntime/Avalonia.DotNetCoreRuntime.csproj
+++ b/src/Avalonia.DotNetCoreRuntime/Avalonia.DotNetCoreRuntime.csproj
@@ -5,7 +5,7 @@
     <DefineConstants>$(DefineConstants);DOTNETCORE</DefineConstants>
   </PropertyGroup>
   <PropertyGroup>
-    <DocumentationFile>bin\$(Configuration)\Avalonia.DotNetCoreRuntime.XML</DocumentationFile>
+    <DocumentationFile>bin\$(Configuration)\Avalonia.DotNetCoreRuntime.xml</DocumentationFile>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="..\Shared\SharedAssemblyInfo.cs">
diff --git a/src/Avalonia.Input/Avalonia.Input.csproj b/src/Avalonia.Input/Avalonia.Input.csproj
index 901f7b5675..c82601ac2c 100644
--- a/src/Avalonia.Input/Avalonia.Input.csproj
+++ b/src/Avalonia.Input/Avalonia.Input.csproj
@@ -11,7 +11,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Input.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Input.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
@@ -21,7 +21,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Input.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Input.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
diff --git a/src/Avalonia.Input/KeyGesture.cs b/src/Avalonia.Input/KeyGesture.cs
index 88d3c99839..954333b80f 100644
--- a/src/Avalonia.Input/KeyGesture.cs
+++ b/src/Avalonia.Input/KeyGesture.cs
@@ -111,6 +111,21 @@ namespace Avalonia.Input
             return string.Join(" + ", parts);
         }
 
-        public bool Matches(KeyEventArgs keyEvent) => keyEvent.Key == Key && keyEvent.Modifiers == Modifiers;
+        public bool Matches(KeyEventArgs keyEvent) => ResolveNumPadOperationKey(keyEvent.Key) == Key && keyEvent.Modifiers == Modifiers;
+
+        private Key ResolveNumPadOperationKey(Key key)
+        {
+            switch (key)
+            {
+                case Key.Add:
+                    return Key.OemPlus;
+                case Key.Subtract:
+                    return Key.OemMinus;
+                case Key.Decimal:
+                    return Key.OemPeriod;
+                default:
+                    return key;
+            }
+        }
     }
 }
diff --git a/src/Avalonia.Interactivity/Avalonia.Interactivity.csproj b/src/Avalonia.Interactivity/Avalonia.Interactivity.csproj
index d683c77468..4f6f9ad6fe 100644
--- a/src/Avalonia.Interactivity/Avalonia.Interactivity.csproj
+++ b/src/Avalonia.Interactivity/Avalonia.Interactivity.csproj
@@ -11,7 +11,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Interactivity.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Interactivity.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
@@ -21,7 +21,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Interactivity.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Interactivity.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
diff --git a/src/Avalonia.Layout/Avalonia.Layout.csproj b/src/Avalonia.Layout/Avalonia.Layout.csproj
index 810a985e36..58c18921f5 100644
--- a/src/Avalonia.Layout/Avalonia.Layout.csproj
+++ b/src/Avalonia.Layout/Avalonia.Layout.csproj
@@ -11,7 +11,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Layout.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Layout.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
@@ -21,7 +21,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Layout.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Layout.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
diff --git a/src/Avalonia.Logging.Serilog/Avalonia.Logging.Serilog.csproj b/src/Avalonia.Logging.Serilog/Avalonia.Logging.Serilog.csproj
index b9fa2f208b..4d9d141d0d 100644
--- a/src/Avalonia.Logging.Serilog/Avalonia.Logging.Serilog.csproj
+++ b/src/Avalonia.Logging.Serilog/Avalonia.Logging.Serilog.csproj
@@ -11,7 +11,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Logging.Serilog.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Logging.Serilog.xml</DocumentationFile>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
     <DebugType>pdbonly</DebugType>
@@ -20,7 +20,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Logging.Serilog.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Logging.Serilog.xml</DocumentationFile>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
   <ItemGroup>
@@ -28,6 +28,7 @@
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Avalonia.Base\Avalonia.Base.csproj" />
+    <ProjectReference Include="..\Avalonia.Controls\Avalonia.Controls.csproj" />
   </ItemGroup>
   <Import Project="..\..\build\Serilog.props" />
 </Project>
\ No newline at end of file
diff --git a/src/Avalonia.Logging.Serilog/SerilogExtensions.cs b/src/Avalonia.Logging.Serilog/SerilogExtensions.cs
new file mode 100644
index 0000000000..6abc7e4684
--- /dev/null
+++ b/src/Avalonia.Logging.Serilog/SerilogExtensions.cs
@@ -0,0 +1,51 @@
+using System;
+using Avalonia.Controls;
+using Serilog;
+using SerilogLevel = Serilog.Events.LogEventLevel;
+
+namespace Avalonia.Logging.Serilog
+{
+    /// <summary>
+    /// Extension methods for Serilog logging.
+    /// </summary>
+    public static class SerilogExtensions
+    {
+        /// <summary>
+        /// Logs Avalonia events to the <see cref="System.Diagnostics.Debug"/> sink.
+        /// </summary>
+        /// <typeparam name="T">The application class type.</typeparam>
+        /// <param name="builder">The app builder instance.</param>
+        /// <param name="level">The minimum level to log.</param>
+        /// <returns>The app builder instance.</returns>
+        public static T LogToDebug<T>(
+            this T builder,
+            LogEventLevel level = LogEventLevel.Warning)
+                where T : AppBuilderBase<T>, new()
+        {
+            SerilogLogger.Initialize(new LoggerConfiguration()
+                .MinimumLevel.Is((SerilogLevel)level)
+                .WriteTo.Debug(outputTemplate: "{Area}: {Message}")
+                .CreateLogger());
+            return builder;
+        }
+
+        /// <summary>
+        /// Logs Avalonia events to the <see cref="System.Diagnostics.Trace"/> sink.
+        /// </summary>
+        /// <typeparam name="T">The application class type.</typeparam>
+        /// <param name="builder">The app builder instance.</param>
+        /// <param name="level">The minimum level to log.</param>
+        /// <returns>The app builder instance.</returns>
+        public static T LogToTrace<T>(
+            this T builder,
+            LogEventLevel level = LogEventLevel.Warning)
+                where T : AppBuilderBase<T>, new()
+        {
+            SerilogLogger.Initialize(new LoggerConfiguration()
+                .MinimumLevel.Is((SerilogLevel)level)
+                .WriteTo.Trace(outputTemplate: "{Area}: {Message}")
+                .CreateLogger());
+            return builder;
+        }
+    }
+}
diff --git a/src/Avalonia.Remote.Protocol/BsonStreamTransport.cs b/src/Avalonia.Remote.Protocol/BsonStreamTransport.cs
index 604703cac8..93a3b60599 100644
--- a/src/Avalonia.Remote.Protocol/BsonStreamTransport.cs
+++ b/src/Avalonia.Remote.Protocol/BsonStreamTransport.cs
@@ -64,7 +64,6 @@ namespace Avalonia.Remote.Protocol
 
         async Task Reader()
         {
-            Task.Yield();
             try
             {
                 while (true)
@@ -147,4 +146,4 @@ namespace Avalonia.Remote.Protocol
         public event Action<IAvaloniaRemoteTransportConnection, object> OnMessage;
         public event Action<IAvaloniaRemoteTransportConnection, Exception> OnException;
     }
-}
\ No newline at end of file
+}
diff --git a/src/Avalonia.Styling/Avalonia.Styling.csproj b/src/Avalonia.Styling/Avalonia.Styling.csproj
index 6c0b957bf4..b8083b52db 100644
--- a/src/Avalonia.Styling/Avalonia.Styling.csproj
+++ b/src/Avalonia.Styling/Avalonia.Styling.csproj
@@ -12,7 +12,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Styling.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Styling.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
@@ -22,7 +22,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Styling.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Styling.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
diff --git a/src/Avalonia.Styling/Styling/Setter.cs b/src/Avalonia.Styling/Styling/Setter.cs
index 95db18a465..e4d0ce5fab 100644
--- a/src/Avalonia.Styling/Styling/Setter.cs
+++ b/src/Avalonia.Styling/Styling/Setter.cs
@@ -174,7 +174,7 @@ namespace Avalonia.Styling
             }
             else
             {
-                return sourceInstance.WithPriority(BindingPriority.StyleTrigger);
+                return sourceInstance.WithPriority(BindingPriority.Style);
             }
         }
     }
diff --git a/src/Avalonia.Themes.Default/Avalonia.Themes.Default.csproj b/src/Avalonia.Themes.Default/Avalonia.Themes.Default.csproj
index b4b200834b..d8260226e9 100644
--- a/src/Avalonia.Themes.Default/Avalonia.Themes.Default.csproj
+++ b/src/Avalonia.Themes.Default/Avalonia.Themes.Default.csproj
@@ -11,7 +11,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Themes.Default.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Themes.Default.xml</DocumentationFile>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
     <DebugType>pdbonly</DebugType>
@@ -20,7 +20,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Themes.Default.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Themes.Default.xml</DocumentationFile>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
   <ItemGroup>
diff --git a/src/Avalonia.Themes.Default/Button.xaml b/src/Avalonia.Themes.Default/Button.xaml
index 908f293fa7..94fcce5e0c 100644
--- a/src/Avalonia.Themes.Default/Button.xaml
+++ b/src/Avalonia.Themes.Default/Button.xaml
@@ -13,8 +13,8 @@
                           Background="{TemplateBinding Background}"
                           BorderBrush="{TemplateBinding BorderBrush}"
                           BorderThickness="{TemplateBinding BorderThickness}"
-                          Content="{TemplateBinding Content}"
                           ContentTemplate="{TemplateBinding ContentTemplate}"
+                          Content="{TemplateBinding Content}"
                           Padding="{TemplateBinding Padding}"
                           TextBlock.Foreground="{TemplateBinding Foreground}"
                           HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
diff --git a/src/Avalonia.Themes.Default/Calendar.xaml b/src/Avalonia.Themes.Default/Calendar.xaml
new file mode 100644
index 0000000000..5e4306c217
--- /dev/null
+++ b/src/Avalonia.Themes.Default/Calendar.xaml
@@ -0,0 +1,30 @@
+<!--
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+-->
+
+<Styles xmlns="https://github.com/avaloniaui">
+  <Style Selector="Calendar">
+    <!--<Setter Property="Focusable" Value="False" />-->
+    <Setter Property="BorderThickness" Value="{DynamicResource ThemeBorderThickness}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderDarkBrush}" />
+    <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}" />
+    <Setter Property="HeaderBackground" Value="{DynamicResource ThemeAccentBrush2}" />
+    <Setter Property="Template">
+      <ControlTemplate>
+        <StackPanel Name="Root"
+                    HorizontalAlignment="Center">
+
+          <CalendarItem Name="CalendarItem"
+                        Background="{TemplateBinding Background}"
+                        BorderBrush="{TemplateBinding BorderBrush}"
+                        BorderThickness="{TemplateBinding BorderThickness}"
+                        HeaderBackground="{TemplateBinding HeaderBackground}"/>
+
+        </StackPanel>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+</Styles>
\ No newline at end of file
diff --git a/src/Avalonia.Themes.Default/CalendarButton.xaml b/src/Avalonia.Themes.Default/CalendarButton.xaml
new file mode 100644
index 0000000000..84969c135f
--- /dev/null
+++ b/src/Avalonia.Themes.Default/CalendarButton.xaml
@@ -0,0 +1,80 @@
+<!--
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+-->
+
+<Styles xmlns="https://github.com/avaloniaui">
+  <Style Selector="CalendarButton">
+    <Setter Property="Background" Value="{DynamicResource ThemeAccentBrush2}" />
+    <Setter Property="FontSize" Value="{DynamicResource FontSizeSmall}" />
+    <Setter Property="HorizontalContentAlignment" Value="Center" />
+    <Setter Property="VerticalContentAlignment" Value="Center" />
+    <Setter Property="MinWidth" Value="37" />
+    <Setter Property="MinHeight" Value="38" />
+    <Setter Property="Focusable" Value="False"/>
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Grid>
+
+          <Rectangle Name="SelectedBackground"
+                     Opacity="0.75"
+                     Fill="{TemplateBinding Background}"/>
+
+          <Rectangle Name="Background"
+                     Opacity="0.5"
+                     Fill="{TemplateBinding Background}"/>
+
+          <!--Focusable="False"-->
+          <ContentControl Name="Content"
+                          Foreground="#FF333333"
+                          ContentTemplate="{TemplateBinding ContentTemplate}"
+                          Content="{TemplateBinding Content}"
+                          HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
+                          VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
+                          FontSize="{TemplateBinding FontSize}"
+                          Margin="1,0,1,1"/>
+
+          <Rectangle Name="FocusVisual"
+                     StrokeThickness="1"
+                     Stroke="{DynamicResource HighlightBrush}"
+                     IsHitTestVisible="False"/>
+
+        </Grid>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="CalendarButton /template/ Rectangle#Background">
+    <Setter Property="IsVisible" Value="False"/>
+  </Style>
+  <Style Selector="CalendarButton:pointerover /template/ Rectangle#Background">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+  <Style Selector="CalendarButton:pressed /template/ Rectangle#Background">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+
+  <Style Selector="CalendarButton /template/ Rectangle#SelectedBackground">
+    <Setter Property="IsVisible" Value="False"/>
+  </Style>
+  <Style Selector="CalendarButton:selected /template/ Rectangle#SelectedBackground">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+
+  <Style Selector="CalendarButton /template/ ContentControl#Content">
+    <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
+  </Style>
+  <Style Selector="CalendarButton:inactive /template/ ContentControl#Content">
+    <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundLightBrush}"/>
+  </Style>
+
+
+  <Style Selector="CalendarButton /template/ Rectangle#FocusVisual">
+    <Setter Property="IsVisible" Value="False"/>
+  </Style>
+  <Style Selector="CalendarButton:btnfocused /template/ Rectangle#FocusVisual">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+</Styles>
\ No newline at end of file
diff --git a/src/Avalonia.Themes.Default/CalendarDayButton.xaml b/src/Avalonia.Themes.Default/CalendarDayButton.xaml
new file mode 100644
index 0000000000..ee7afdc73b
--- /dev/null
+++ b/src/Avalonia.Themes.Default/CalendarDayButton.xaml
@@ -0,0 +1,116 @@
+<!--
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+-->
+
+<Styles xmlns="https://github.com/avaloniaui">
+  <Style Selector="CalendarDayButton">
+    <Setter Property="Background" Value="{DynamicResource ThemeAccentBrush2}" />
+    <Setter Property="FontSize" Value="{DynamicResource FontSizeSmall}" />
+    <Setter Property="HorizontalContentAlignment" Value="Center" />
+    <Setter Property="VerticalContentAlignment" Value="Center" />
+    <Setter Property="MinWidth" Value="5" />
+    <Setter Property="MinHeight" Value="5" />
+    <Setter Property="Focusable" Value="False"/>
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Panel Background="Transparent">
+
+          <Rectangle Name="TodayBackground"
+                     Fill="{DynamicResource HighlightBrush}"/>
+
+          <Rectangle Name="SelectedBackground"
+                     Opacity="0.75"
+                     Fill="{TemplateBinding Background}"/>
+
+          <Rectangle Name="Background"
+                     Opacity="0.5"
+                     Fill="{TemplateBinding Background}"/>
+
+          <ContentControl Name="Content"
+                          ContentTemplate="{TemplateBinding ContentTemplate}"
+                          Content="{TemplateBinding Content}"
+                          HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
+                          VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
+                          FontSize="{TemplateBinding FontSize}"
+                          Margin="5,1,5,1"/>
+
+          <Path Name="BlackoutVisual"
+                Margin="3"
+                HorizontalAlignment="Stretch"
+                VerticalAlignment="Stretch"
+                RenderTransformOrigin="0.5,0.5"
+                Fill="#FF000000"
+                Stretch="Fill"
+                Data="M8.1772461,11.029181 L10.433105,11.029181 L11.700684,12.801641 L12.973633,11.029181 L15.191895,11.029181 L12.844727,13.999395 L15.21875,17.060919 L12.962891,17.060919 L11.673828,15.256231 L10.352539,17.060919 L8.1396484,17.060919 L10.519043,14.042364 z" />
+          
+          <Rectangle Name="FocusVisual"
+                     StrokeThickness="1"
+                     Stroke="{DynamicResource HighlightBrush}"
+                     IsHitTestVisible="False"/>
+
+        </Panel>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="CalendarDayButton /template/ Rectangle#Background">
+    <Setter Property="IsVisible" Value="False"/>
+  </Style>
+  <Style Selector="CalendarDayButton:pointerover /template/ Rectangle#Background">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+  <Style Selector="CalendarDayButton:pressed /template/ Rectangle#Background">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+
+  <Style Selector="CalendarDayButton /template/ Rectangle#SelectedBackground">
+    <Setter Property="IsVisible" Value="False"/>
+  </Style>
+  <Style Selector="CalendarDayButton:selected /template/ Rectangle#SelectedBackground">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+
+  <Style Selector="CalendarDayButton /template/ ContentControl#Content">
+    <Setter Property="Opacity" Value="1"/>
+    <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
+  </Style>
+  <Style Selector="CalendarDayButton:disabled /template/ Rectangle#Background">
+    <Setter Property="IsVisible" Value="False"/>
+  </Style>
+  <Style Selector="CalendarDayButton:disabled /template/ ContentControl#Content">
+    <Setter Property="Opacity" Value="0.3"/>
+  </Style>
+
+  <Style Selector="CalendarDayButton /template/ Rectangle#FocusVisual">
+    <Setter Property="IsVisible" Value="False"/>
+  </Style>
+  <Style Selector="CalendarDayButton:dayfocused /template/ Rectangle#FocusVisual">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+
+  <Style Selector="CalendarDayButton /template/ Rectangle#TodayBackground">
+    <Setter Property="IsVisible" Value="False"/>
+  </Style>
+  <Style Selector="CalendarDayButton:today /template/ Rectangle#TodayBackground">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+
+
+  <Style Selector="CalendarDayButton:inactive /template/ ContentControl#Content">
+    <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundLightBrush}"/>
+  </Style>
+  <Style Selector="CalendarDayButton:today /template/ ContentControl#Content">
+    <Setter Property="Foreground" Value="#FFFFFFFF"/>
+  </Style>
+
+  <Style Selector="CalendarDayButton /template/ Path#BlackoutVisual">
+    <Setter Property="Opacity" Value="0"/>
+  </Style>
+  <Style Selector="CalendarDayButton:blackout /template/ Path#BlackoutVisual">
+    <Setter Property="Opacity" Value="0.3"/>
+  </Style>  
+
+</Styles>
\ No newline at end of file
diff --git a/src/Avalonia.Themes.Default/CalendarItem.xaml b/src/Avalonia.Themes.Default/CalendarItem.xaml
new file mode 100644
index 0000000000..a9756fdb5f
--- /dev/null
+++ b/src/Avalonia.Themes.Default/CalendarItem.xaml
@@ -0,0 +1,183 @@
+<!--
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+-->
+
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+  <Style Selector="CalendarItem">
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Panel>
+          <Border BorderThickness="{TemplateBinding BorderThickness}"
+                  BorderBrush="{TemplateBinding BorderBrush}"
+                  Background="{TemplateBinding Background}"
+                  Margin="0,2,0,2"
+                  CornerRadius="1">
+
+            <Border CornerRadius="1"
+                    BorderBrush="{DynamicResource ThemeBackgroundBrush}"
+                    BorderThickness="2">
+              <Grid>
+                <Grid.RowDefinitions>
+                  <RowDefinition Height="Auto" />
+                  <RowDefinition Height="*" />
+                </Grid.RowDefinitions>
+                <Grid.ColumnDefinitions>
+                  <ColumnDefinition Width="Auto" />
+                  <ColumnDefinition Width="Auto" />
+                  <ColumnDefinition Width="Auto" />
+                </Grid.ColumnDefinitions>
+
+                <Grid.Styles>
+                  <Style Selector="Button.CalendarHeader">
+                    <Setter Property="Cursor" Value="Hand"/>
+                    <Setter Property="Background" Value="Transparent"/>
+                    <Setter Property="BorderThickness" Value="0"/>
+                  </Style>
+                    <Style Selector="Button.CalendarHeader:pressed  /template/ ContentPresenter">
+                    <Setter Property="Background" Value="Transparent"/>
+                  </Style>
+
+                  <Style Selector="Button.CalendarNavigation">
+                    <Setter Property="Height" Value="20"/>
+                    <Setter Property="Width" Value="28"/>
+                  </Style>
+                  <Style Selector="Button.CalendarNavigation > Path">
+                    <Setter Property="Fill" Value="{DynamicResource ThemeForegroundBrush}"/>
+                  </Style>
+                  <Style Selector="Button.CalendarNavigation:pointerover > Path">
+                    <Setter Property="Fill" Value="{DynamicResource HighlightBrush}"/>
+                  </Style>
+
+                  <Style Selector="Button#HeaderButton:pointerover">
+                    <Setter Property="Foreground" Value="{DynamicResource HighlightBrush}"/>
+                  </Style>
+                </Grid.Styles>
+
+                <Rectangle Grid.ColumnSpan="3"
+                           Fill="{TemplateBinding HeaderBackground}"
+                           Stretch="Fill"
+                           VerticalAlignment="Top"
+                           Height="22"/>
+
+                <Button Name="PreviousButton"
+                        Classes="CalendarHeader CalendarNavigation"
+                        IsVisible="False"
+                        HorizontalAlignment="Left">
+
+                  <Path Margin="14,-6,0,0"
+                        Height="10"
+                        Width="6"
+                        VerticalAlignment="Center"
+                        HorizontalAlignment="Left"
+                        Stretch="Fill"
+                        Data="M288.75,232.25 L288.75,240.625 L283,236.625 z" />
+                  
+                </Button>
+                
+                <Button Name="HeaderButton"
+                        Classes="CalendarHeader"
+                        Grid.Column="1"
+                        FontWeight="Bold"
+                        FontSize="10.5"
+                        HorizontalAlignment="Center"
+                        VerticalAlignment="Center" 
+                        Padding="1,5,1,9"/>
+
+                <Button Name="NextButton"
+                        Classes="CalendarHeader CalendarNavigation"
+                        Grid.Column="2"
+                        IsVisible="False"
+                        HorizontalAlignment="Right" >
+
+                  <Path Margin="0,-6,14,0"
+                        Height="10"
+                        Width="6"
+                        Stretch="Fill"
+                        VerticalAlignment="Center"
+                        HorizontalAlignment="Right"
+                        Data="M282.875,231.875 L282.875,240.375 L288.625,236 z" />
+                  
+                </Button>
+
+                <Grid Name="MonthView"
+                      Grid.Row="1"
+                      Grid.ColumnSpan="3"
+                      IsVisible="False"
+                      Margin="6,-1,6,6">
+                  <Grid.RowDefinitions>
+                    <RowDefinition Height="Auto" />
+                    <RowDefinition Height="Auto" />
+                    <RowDefinition Height="Auto" />
+                    <RowDefinition Height="Auto" />
+                    <RowDefinition Height="Auto" />
+                    <RowDefinition Height="Auto" />
+                    <RowDefinition Height="Auto" />
+                  </Grid.RowDefinitions>
+                  <Grid.ColumnDefinitions>
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                  </Grid.ColumnDefinitions>
+                </Grid>
+
+                <Grid Name="YearView"
+                      Grid.Row="1"
+                      Grid.ColumnSpan="3"
+                      IsVisible="False"
+                      Margin="6,-3,7,6">
+                  <Grid.RowDefinitions>
+                    <RowDefinition Height="Auto" />
+                    <RowDefinition Height="Auto" />
+                    <RowDefinition Height="Auto" />
+                  </Grid.RowDefinitions>
+                  <Grid.ColumnDefinitions>
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                  </Grid.ColumnDefinitions>
+                </Grid>
+
+              </Grid>
+            </Border>
+          </Border>
+
+
+          <Rectangle Name="DisabledVisual"
+                     Stretch="Fill"
+                     Fill="#FFFFFFFF"
+                     Opacity="{DynamicResource ThemeDisabledOpacity}"
+                     Margin="0,2,0,2" />
+
+        </Panel>
+      </ControlTemplate>
+    </Setter>
+    <Setter Property="DayTitleTemplate">
+      <Template>
+        <TextBlock FontWeight="Bold"
+                   FontSize="9.5"
+                   Margin="0,4,0,4"
+                   HorizontalAlignment="Center"
+                   VerticalAlignment="Center"
+                   Text="{Binding}" />
+      </Template>
+
+    </Setter>
+  </Style>
+
+  <Style Selector="CalendarItem /template/ Rectangle#DisabledVisual">
+    <Setter Property="IsVisible" Value="False"/>
+  </Style>
+  <Style Selector="CalendarItem:calendardisabled /template/ Rectangle#DisabledVisual">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+  
+</Styles>
\ No newline at end of file
diff --git a/src/Avalonia.Themes.Default/CheckBox.xaml b/src/Avalonia.Themes.Default/CheckBox.xaml
index 195ec098c9..62a05a3525 100644
--- a/src/Avalonia.Themes.Default/CheckBox.xaml
+++ b/src/Avalonia.Themes.Default/CheckBox.xaml
@@ -12,18 +12,27 @@
                   Width="18"
                   Height="18"
                   VerticalAlignment="Center">
-            <Path Name="checkMark"
-                  Fill="{DynamicResource HighlightBrush}"
-                  Width="11"
-                  Height="10"
-                  Stretch="Uniform"
-                  HorizontalAlignment="Center"
-                  VerticalAlignment="Center"
-                  Data="M 1145.607177734375,430 C1145.607177734375,430 1141.449951171875,435.0772705078125 1141.449951171875,435.0772705078125 1141.449951171875,435.0772705078125 1139.232177734375,433.0999755859375 1139.232177734375,433.0999755859375 1139.232177734375,433.0999755859375 1138,434.5538330078125 1138,434.5538330078125 1138,434.5538330078125 1141.482177734375,438 1141.482177734375,438 1141.482177734375,438 1141.96875,437.9375 1141.96875,437.9375 1141.96875,437.9375 1147,431.34619140625 1147,431.34619140625 1147,431.34619140625 1145.607177734375,430 1145.607177734375,430 z"/>
+            <Panel>
+              <Path Name="checkMark"
+                    Fill="{DynamicResource HighlightBrush}"
+                    Width="11"
+                    Height="10"
+                    Stretch="Uniform"
+                    HorizontalAlignment="Center"
+                    VerticalAlignment="Center"
+                    Data="M 1145.607177734375,430 C1145.607177734375,430 1141.449951171875,435.0772705078125 1141.449951171875,435.0772705078125 1141.449951171875,435.0772705078125 1139.232177734375,433.0999755859375 1139.232177734375,433.0999755859375 1139.232177734375,433.0999755859375 1138,434.5538330078125 1138,434.5538330078125 1138,434.5538330078125 1141.482177734375,438 1141.482177734375,438 1141.482177734375,438 1141.96875,437.9375 1141.96875,437.9375 1141.96875,437.9375 1147,431.34619140625 1147,431.34619140625 1147,431.34619140625 1145.607177734375,430 1145.607177734375,430 z"/>
+              <Rectangle Name="indeterminateMark"
+                         Fill="{DynamicResource HighlightBrush}"
+                         Width="10"
+                         Height="10"
+                         Stretch="Uniform"
+                         HorizontalAlignment="Center"
+                         VerticalAlignment="Center"/>
+            </Panel>
           </Border>
           <ContentPresenter Name="PART_ContentPresenter"
-                            Content="{TemplateBinding Content}"
                             ContentTemplate="{TemplateBinding ContentTemplate}"
+                            Content="{TemplateBinding Content}"
                             Margin="4,0,0,0"
                             VerticalAlignment="Center"
                             Grid.Column="1"/>
@@ -37,9 +46,15 @@
   <Style Selector="CheckBox /template/ Path#checkMark">
     <Setter Property="IsVisible" Value="False"/>
   </Style>
+  <Style Selector="CheckBox /template/ Rectangle#indeterminateMark">
+    <Setter Property="IsVisible" Value="False"/>
+  </Style>
   <Style Selector="CheckBox:checked /template/ Path#checkMark">
     <Setter Property="IsVisible" Value="True"/>
   </Style>
+  <Style Selector="CheckBox:indeterminate /template/ Rectangle#indeterminateMark">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
   <Style Selector="CheckBox:disabled /template/ Border#border">
     <Setter Property="Opacity" Value="{DynamicResource ThemeDisabledOpacity}"/>
   </Style>
diff --git a/src/Avalonia.Themes.Default/ContentControl.xaml b/src/Avalonia.Themes.Default/ContentControl.xaml
index 27f6648548..7584ae0dfe 100644
--- a/src/Avalonia.Themes.Default/ContentControl.xaml
+++ b/src/Avalonia.Themes.Default/ContentControl.xaml
@@ -5,8 +5,8 @@
                         Background="{TemplateBinding Background}"
                         BorderBrush="{TemplateBinding BorderBrush}"
                         BorderThickness="{TemplateBinding BorderThickness}"
-                        Content="{TemplateBinding Content}"
                         ContentTemplate="{TemplateBinding ContentTemplate}"
+                        Content="{TemplateBinding Content}"
                         Padding="{TemplateBinding Padding}"/>
     </ControlTemplate>
   </Setter>
diff --git a/src/Avalonia.Themes.Default/DefaultTheme.xaml b/src/Avalonia.Themes.Default/DefaultTheme.xaml
index 48f530cca8..ae00f0757a 100644
--- a/src/Avalonia.Themes.Default/DefaultTheme.xaml
+++ b/src/Avalonia.Themes.Default/DefaultTheme.xaml
@@ -36,4 +36,8 @@
   <StyleInclude Source="resm:Avalonia.Themes.Default.TreeViewItem.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.Window.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.EmbeddableControlRoot.xaml?assembly=Avalonia.Themes.Default"/>
+  <StyleInclude Source="resm:Avalonia.Themes.Default.CalendarButton.xaml?assembly=Avalonia.Themes.Default"/>
+  <StyleInclude Source="resm:Avalonia.Themes.Default.CalendarDayButton.xaml?assembly=Avalonia.Themes.Default"/>
+  <StyleInclude Source="resm:Avalonia.Themes.Default.CalendarItem.xaml?assembly=Avalonia.Themes.Default"/>
+  <StyleInclude Source="resm:Avalonia.Themes.Default.Calendar.xaml?assembly=Avalonia.Themes.Default"/>
 </Styles>
diff --git a/src/Avalonia.Themes.Default/DropDownItem.xaml b/src/Avalonia.Themes.Default/DropDownItem.xaml
index 48d791f629..257030d8af 100644
--- a/src/Avalonia.Themes.Default/DropDownItem.xaml
+++ b/src/Avalonia.Themes.Default/DropDownItem.xaml
@@ -10,8 +10,8 @@
                           Background="{TemplateBinding Background}"
                           BorderBrush="{TemplateBinding BorderBrush}"
                           BorderThickness="{TemplateBinding BorderThickness}"
-                          Content="{TemplateBinding Content}"
                           ContentTemplate="{TemplateBinding ContentTemplate}"
+                          Content="{TemplateBinding Content}"
                           HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                           VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
                           Padding="{TemplateBinding Padding}"/>
diff --git a/src/Avalonia.Themes.Default/EmbeddableControlRoot.xaml b/src/Avalonia.Themes.Default/EmbeddableControlRoot.xaml
index f39720bb65..de364c0108 100644
--- a/src/Avalonia.Themes.Default/EmbeddableControlRoot.xaml
+++ b/src/Avalonia.Themes.Default/EmbeddableControlRoot.xaml
@@ -7,8 +7,8 @@
       <Border Background="{TemplateBinding Background}">
         <AdornerDecorator>
           <ContentPresenter Name="PART_ContentPresenter" 
-                            Content="{TemplateBinding Content}" 
                             ContentTemplate="{TemplateBinding ContentTemplate}"
+                            Content="{TemplateBinding Content}" 
                             Margin="{TemplateBinding Padding}"/>
         </AdornerDecorator>
       </Border>
diff --git a/src/Avalonia.Themes.Default/Expander.xaml b/src/Avalonia.Themes.Default/Expander.xaml
index 51efec6b95..5e05dcf608 100644
--- a/src/Avalonia.Themes.Default/Expander.xaml
+++ b/src/Avalonia.Themes.Default/Expander.xaml
@@ -16,8 +16,8 @@
             <ContentPresenter Name="PART_ContentPresenter"
                               Grid.Row="1"
                               IsVisible="{TemplateBinding IsExpanded}"
-                              Content="{TemplateBinding Content}"
                               ContentTemplate="{TemplateBinding ContentTemplate}"
+                              Content="{TemplateBinding Content}"
                               HorizontalAlignment="Stretch"
                               VerticalAlignment="Stretch" />
           </Grid>
@@ -34,8 +34,8 @@
             <ContentPresenter Name="PART_ContentPresenter"
                               Grid.Row="0"
                               IsVisible="{TemplateBinding IsExpanded}"
-                              Content="{TemplateBinding Content}"
                               ContentTemplate="{TemplateBinding ContentTemplate}"
+                              Content="{TemplateBinding Content}"
                               HorizontalAlignment="Stretch"
                               VerticalAlignment="Stretch" />
           </Grid>
@@ -52,8 +52,8 @@
             <ContentPresenter Name="PART_ContentPresenter"
                               Grid.Column="1"
                               IsVisible="{TemplateBinding IsExpanded}"
-                              Content="{TemplateBinding Content}"
                               ContentTemplate="{TemplateBinding ContentTemplate}"
+                              Content="{TemplateBinding Content}"
                               HorizontalAlignment="Stretch"
                               VerticalAlignment="Stretch" />
           </Grid>
@@ -70,8 +70,8 @@
             <ContentPresenter Name="PART_ContentPresenter"
                               Grid.Column="0"
                               IsVisible="{TemplateBinding IsExpanded}"
-                              Content="{TemplateBinding Content}"
                               ContentTemplate="{TemplateBinding ContentTemplate}"
+                              Content="{TemplateBinding Content}"
                               HorizontalAlignment="Stretch"
                               VerticalAlignment="Stretch" />
           </Grid>
diff --git a/src/Avalonia.Themes.Default/LayoutTransformControl.xaml b/src/Avalonia.Themes.Default/LayoutTransformControl.xaml
index c9df62625f..b26f053622 100644
--- a/src/Avalonia.Themes.Default/LayoutTransformControl.xaml
+++ b/src/Avalonia.Themes.Default/LayoutTransformControl.xaml
@@ -5,8 +5,8 @@
                         Background="{TemplateBinding Background}"
                         BorderBrush="{TemplateBinding BorderBrush}"
                         BorderThickness="{TemplateBinding BorderThickness}"
-                        Content="{TemplateBinding Content}" 
                         ContentTemplate="{TemplateBinding ContentTemplate}"
+                        Content="{TemplateBinding Content}" 
                         Padding="{TemplateBinding Padding}"/>
     </ControlTemplate>
   </Setter>
diff --git a/src/Avalonia.Themes.Default/ListBoxItem.xaml b/src/Avalonia.Themes.Default/ListBoxItem.xaml
index 64fc62ba73..a0405f2875 100644
--- a/src/Avalonia.Themes.Default/ListBoxItem.xaml
+++ b/src/Avalonia.Themes.Default/ListBoxItem.xaml
@@ -7,8 +7,8 @@
                           Background="{TemplateBinding Background}"
                           BorderBrush="{TemplateBinding BorderBrush}"
                           BorderThickness="{TemplateBinding BorderThickness}"
-                          Content="{TemplateBinding Content}"
                           ContentTemplate="{TemplateBinding ContentTemplate}"
+                          Content="{TemplateBinding Content}"
                           Padding="{TemplateBinding Padding}"/>
       </ControlTemplate>
     </Setter>
diff --git a/src/Avalonia.Themes.Default/PopupRoot.xaml b/src/Avalonia.Themes.Default/PopupRoot.xaml
index 47e519bf90..cc23367ac0 100644
--- a/src/Avalonia.Themes.Default/PopupRoot.xaml
+++ b/src/Avalonia.Themes.Default/PopupRoot.xaml
@@ -4,8 +4,8 @@
     <ControlTemplate>
       <ContentPresenter Name="PART_ContentPresenter"
                         Background="{TemplateBinding Background}"
-                        Content="{TemplateBinding Content}" 
                         ContentTemplate="{TemplateBinding ContentTemplate}"
+                        Content="{TemplateBinding Content}" 
                         Padding="{TemplateBinding Padding}"/>
     </ControlTemplate>
   </Setter>
diff --git a/src/Avalonia.Themes.Default/RadioButton.xaml b/src/Avalonia.Themes.Default/RadioButton.xaml
index 996f46023e..fb71432595 100644
--- a/src/Avalonia.Themes.Default/RadioButton.xaml
+++ b/src/Avalonia.Themes.Default/RadioButton.xaml
@@ -20,9 +20,17 @@
                    UseLayoutRounding="False"
                    HorizontalAlignment="Center"
                    VerticalAlignment="Center"/>
+          <Ellipse Name="indeterminateMark"
+                   Fill="{DynamicResource ThemeAccentBrush}"
+                   Width="10"
+                   Height="10"
+                   Stretch="Uniform"
+                   UseLayoutRounding="False"
+                   HorizontalAlignment="Center"
+                   VerticalAlignment="Center"/>
           <ContentPresenter Name="PART_ContentPresenter"
-                            Content="{TemplateBinding Content}"
                             ContentTemplate="{TemplateBinding ContentTemplate}"
+                            Content="{TemplateBinding Content}"
                             Margin="4,0,0,0"
                             VerticalAlignment="Center"
                             Grid.Column="1"/>
@@ -36,9 +44,15 @@
   <Style Selector="RadioButton /template/ Ellipse#checkMark">
     <Setter Property="IsVisible" Value="False"/>
   </Style>
+  <Style Selector="RadioButton /template/ Ellipse#indeterminateMark">
+    <Setter Property="IsVisible" Value="False"/>
+  </Style>
   <Style Selector="RadioButton:checked /template/ Ellipse#checkMark">
     <Setter Property="IsVisible" Value="True"/>
   </Style>
+  <Style Selector="RadioButton:indeterminate /template/ Ellipse#indeterminateMark">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
   <Style Selector="RadioButton:disabled /template/ Ellipse#border">
     <Setter Property="Opacity" Value="{DynamicResource ThemeDisabledOpacity}"/>
   </Style>
diff --git a/src/Avalonia.Themes.Default/RepeatButton.xaml b/src/Avalonia.Themes.Default/RepeatButton.xaml
index 1caaa266de..872f390ac5 100644
--- a/src/Avalonia.Themes.Default/RepeatButton.xaml
+++ b/src/Avalonia.Themes.Default/RepeatButton.xaml
@@ -20,8 +20,8 @@
                                   Background="{TemplateBinding Background}"
                                   BorderBrush="{TemplateBinding BorderBrush}"
                                   BorderThickness="{TemplateBinding BorderThickness}"
-                                  Content="{TemplateBinding Content}"
                                   ContentTemplate="{TemplateBinding ContentTemplate}"
+                                  Content="{TemplateBinding Content}"
                                   Padding="{TemplateBinding Padding}"
                                   TextBlock.Foreground="{TemplateBinding Foreground}"
                                   HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
diff --git a/src/Avalonia.Themes.Default/TabStripItem.xaml b/src/Avalonia.Themes.Default/TabStripItem.xaml
index 7f7fef0a1a..408cfaa3d7 100644
--- a/src/Avalonia.Themes.Default/TabStripItem.xaml
+++ b/src/Avalonia.Themes.Default/TabStripItem.xaml
@@ -9,8 +9,8 @@
                           Background="{TemplateBinding Background}"
                           BorderBrush="{TemplateBinding BorderBrush}"
                           BorderThickness="{TemplateBinding BorderThickness}"
-                          Content="{TemplateBinding Content}"
                           ContentTemplate="{TemplateBinding ContentTemplate}"
+                          Content="{TemplateBinding Content}"
                           Padding="{TemplateBinding Padding}"/>
       </ControlTemplate>
     </Setter>
diff --git a/src/Avalonia.Themes.Default/ToggleButton.xaml b/src/Avalonia.Themes.Default/ToggleButton.xaml
index 12d7daacda..dadc45d854 100644
--- a/src/Avalonia.Themes.Default/ToggleButton.xaml
+++ b/src/Avalonia.Themes.Default/ToggleButton.xaml
@@ -13,8 +13,8 @@
                           Background="{TemplateBinding Background}"
                           BorderBrush="{TemplateBinding BorderBrush}"
                           BorderThickness="{TemplateBinding BorderThickness}"
-                          Content="{TemplateBinding Content}"
                           ContentTemplate="{TemplateBinding ContentTemplate}"
+                          Content="{TemplateBinding Content}"
                           Padding="{TemplateBinding Padding}"
                           TextBlock.Foreground="{TemplateBinding Foreground}"
                           HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
diff --git a/src/Avalonia.Themes.Default/ToolTip.xaml b/src/Avalonia.Themes.Default/ToolTip.xaml
index f3e819c101..1fc0202dd3 100644
--- a/src/Avalonia.Themes.Default/ToolTip.xaml
+++ b/src/Avalonia.Themes.Default/ToolTip.xaml
@@ -9,8 +9,8 @@
                         Background="{TemplateBinding Background}"
                         BorderBrush="{TemplateBinding BorderBrush}"
                         BorderThickness="{TemplateBinding BorderThickness}"
-                        Content="{TemplateBinding Content}" 
                         ContentTemplate="{TemplateBinding ContentTemplate}"
+                        Content="{TemplateBinding Content}" 
                         Padding="{TemplateBinding Padding}"/>
     </ControlTemplate>
   </Setter>
diff --git a/src/Avalonia.Themes.Default/Window.xaml b/src/Avalonia.Themes.Default/Window.xaml
index 06922addad..d19bf41c4d 100644
--- a/src/Avalonia.Themes.Default/Window.xaml
+++ b/src/Avalonia.Themes.Default/Window.xaml
@@ -7,8 +7,8 @@
       <Border Background="{TemplateBinding Background}">
         <AdornerDecorator>
           <ContentPresenter Name="PART_ContentPresenter" 
-                            Content="{TemplateBinding Content}" 
                             ContentTemplate="{TemplateBinding ContentTemplate}"
+                            Content="{TemplateBinding Content}" 
                             Margin="{TemplateBinding Padding}"/>
         </AdornerDecorator>
       </Border>
diff --git a/src/Avalonia.Visuals/Animation/PageSlide.cs b/src/Avalonia.Visuals/Animation/PageSlide.cs
index 015f22ec14..ebc358379d 100644
--- a/src/Avalonia.Visuals/Animation/PageSlide.cs
+++ b/src/Avalonia.Visuals/Animation/PageSlide.cs
@@ -15,6 +15,15 @@ namespace Avalonia.Animation
     /// </summary>
     public class PageSlide : IPageTransition
     {
+        /// <summary>
+        /// The axis on which the PageSlide should occur
+        /// </summary>
+        public enum SlideAxis
+        {
+            Horizontal,
+            Vertical
+        }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="PageSlide"/> class.
         /// </summary>
@@ -26,9 +35,11 @@ namespace Avalonia.Animation
         /// Initializes a new instance of the <see cref="PageSlide"/> class.
         /// </summary>
         /// <param name="duration">The duration of the animation.</param>
-        public PageSlide(TimeSpan duration)
+        /// <param name="orientation">The axis on which the animation should occur</param>
+        public PageSlide(TimeSpan duration, SlideAxis orientation = SlideAxis.Horizontal)
         {
             Duration = duration;
+            Orientation = orientation;
         }
 
         /// <summary>
@@ -36,6 +47,11 @@ namespace Avalonia.Animation
         /// </summary>
         public TimeSpan Duration { get; set; }
 
+        /// <summary>
+        /// Gets the duration of the animation.
+        /// </summary>
+        public SlideAxis Orientation { get; set; }
+
         /// <summary>
         /// Starts the animation.
         /// </summary>
@@ -55,7 +71,8 @@ namespace Avalonia.Animation
         {
             var tasks = new List<Task>();
             var parent = GetVisualParent(from, to);
-            var distance = parent.Bounds.Width;
+            var distance = Orientation == SlideAxis.Horizontal ? parent.Bounds.Width : parent.Bounds.Height;
+            var translateProperty = Orientation == SlideAxis.Horizontal ? TranslateTransform.XProperty : TranslateTransform.YProperty;
 
             if (from != null)
             {
@@ -63,7 +80,7 @@ namespace Avalonia.Animation
                 from.RenderTransform = transform;
                 tasks.Add(Animate.Property(
                     transform,
-                    TranslateTransform.XProperty,
+                    translateProperty,
                     0.0,
                     forward ? -distance : distance,
                     LinearEasing.For<double>(),
@@ -77,7 +94,7 @@ namespace Avalonia.Animation
                 to.IsVisible = true;
                 tasks.Add(Animate.Property(
                     transform,
-                    TranslateTransform.XProperty,
+                    translateProperty,
                     forward ? distance : -distance,
                     0.0,
                     LinearEasing.For<double>(),
diff --git a/src/Avalonia.Visuals/Media/PathMarkupParser.cs b/src/Avalonia.Visuals/Media/PathMarkupParser.cs
index fbc189546c..9e4a3cbeae 100644
--- a/src/Avalonia.Visuals/Media/PathMarkupParser.cs
+++ b/src/Avalonia.Visuals/Media/PathMarkupParser.cs
@@ -320,7 +320,7 @@ namespace Avalonia.Media
                     if (c == 'E')
                     {
                         readSign = false;
-                        readExponent = c == 'E';
+                        readExponent = true;
                     }
                 }
                 else
diff --git a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
index f7befa646a..041d8f8f6b 100644
--- a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
+++ b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
@@ -25,11 +25,9 @@ namespace Avalonia.Rendering
         private readonly IRenderLoop _renderLoop;
         private readonly IVisual _root;
         private readonly ISceneBuilder _sceneBuilder;
-        private readonly RenderLayers _layers;
 
         private bool _running;
         private Scene _scene;
-        private IRenderTarget _renderTarget;
         private DirtyVisuals _dirty;
         private IRenderTargetBitmapImpl _overlay;
         private bool _updateQueued;
@@ -56,7 +54,7 @@ namespace Avalonia.Rendering
             _dispatcher = dispatcher ?? Dispatcher.UIThread;
             _root = root;
             _sceneBuilder = sceneBuilder ?? new SceneBuilder();
-            _layers = new RenderLayers();
+            Layers = new RenderLayers();
             _renderLoop = renderLoop;
         }
 
@@ -78,9 +76,9 @@ namespace Avalonia.Rendering
             Contract.Requires<ArgumentNullException>(renderTarget != null);
 
             _root = root;
-            _renderTarget = renderTarget;
+            RenderTarget = renderTarget;
             _sceneBuilder = sceneBuilder ?? new SceneBuilder();
-            _layers = new RenderLayers();
+            Layers = new RenderLayers();
         }
 
         /// <inheritdoc/>
@@ -94,6 +92,16 @@ namespace Avalonia.Rendering
         /// </summary>
         public string DebugFramesPath { get; set; }
 
+        /// <summary>
+        /// Gets the render layers.
+        /// </summary>
+        internal RenderLayers Layers { get; }
+
+        /// <summary>
+        /// Gets the current render target.
+        /// </summary>
+        internal IRenderTarget RenderTarget { get; private set; }
+
         /// <inheritdoc/>
         public void AddDirty(IVisual visual)
         {
@@ -173,9 +181,9 @@ namespace Avalonia.Rendering
             bool renderOverlay = DrawDirtyRects || DrawFps;
             bool composite = false;
 
-            if (_renderTarget == null)
+            if (RenderTarget == null)
             {
-                _renderTarget = ((IRenderRoot)_root).CreateRenderTarget();
+                RenderTarget = ((IRenderRoot)_root).CreateRenderTarget();
             }
 
             if (renderOverlay)
@@ -191,8 +199,8 @@ namespace Avalonia.Rendering
 
                     if (scene.Generation != _lastSceneId)
                     {
-                        context = _renderTarget.CreateDrawingContext(this);
-                        _layers.Update(scene, context);
+                        context = RenderTarget.CreateDrawingContext(this);
+                        Layers.Update(scene, context);
 
                         RenderToLayers(scene);
 
@@ -208,13 +216,13 @@ namespace Avalonia.Rendering
 
                     if (renderOverlay)
                     {
-                        context = context ?? _renderTarget.CreateDrawingContext(this);
+                        context = context ?? RenderTarget.CreateDrawingContext(this);
                         RenderOverlay(scene, context);
                         RenderComposite(scene, context);
                     }
                     else if (composite)
                     {
-                        context = context ?? _renderTarget.CreateDrawingContext(this);
+                        context = context ?? RenderTarget.CreateDrawingContext(this);
                         RenderComposite(scene, context);
                     }
 
@@ -224,8 +232,8 @@ namespace Avalonia.Rendering
             catch (RenderTargetCorruptedException ex)
             {
                 Logging.Logger.Information("Renderer", this, "Render target was corrupted. Exception: {0}", ex);
-                _renderTarget?.Dispose();
-                _renderTarget = null;
+                RenderTarget?.Dispose();
+                RenderTarget = null;
             }
         }
 
@@ -235,9 +243,11 @@ namespace Avalonia.Rendering
             {
                 clipBounds = node.ClipBounds.Intersect(clipBounds);
 
-                if (!clipBounds.IsEmpty)
+                if (!clipBounds.IsEmpty && node.Opacity > 0)
                 {
-                    node.BeginRender(context);
+                    var isLayerRoot = node.Visual == layer;
+
+                    node.BeginRender(context, isLayerRoot);
 
                     foreach (var operation in node.DrawOperations)
                     {
@@ -251,7 +261,7 @@ namespace Avalonia.Rendering
                         Render(context, (VisualNode)child, layer, clipBounds);
                     }
 
-                    node.EndRender(context);
+                    node.EndRender(context, isLayerRoot);
                 }
             }
         }
@@ -262,7 +272,7 @@ namespace Avalonia.Rendering
             {
                 foreach (var layer in scene.Layers)
                 {
-                    var renderTarget = _layers[layer.LayerRoot].Bitmap;
+                    var renderTarget = Layers[layer.LayerRoot].Bitmap;
                     var node = (VisualNode)scene.FindNode(layer.LayerRoot);
 
                     if (node != null)
@@ -322,7 +332,7 @@ namespace Avalonia.Rendering
 
             foreach (var layer in scene.Layers)
             {
-                var bitmap = _layers[layer.LayerRoot].Bitmap;
+                var bitmap = Layers[layer.LayerRoot].Bitmap;
                 var sourceRect = new Rect(0, 0, bitmap.PixelWidth, bitmap.PixelHeight);
 
                 if (layer.GeometryClip != null)
@@ -353,7 +363,7 @@ namespace Avalonia.Rendering
 
             if (DrawFps)
             {
-                RenderFps(context, clientRect, true);
+                RenderFps(context, clientRect, scene.Layers.Count);
             }
         }
 
@@ -442,7 +452,7 @@ namespace Avalonia.Rendering
         {
             var index = 0;
 
-            foreach (var layer in _layers)
+            foreach (var layer in Layers)
             {
                 var fileName = Path.Combine(DebugFramesPath, $"frame-{id}-layer-{index++}.png");
                 layer.Bitmap.Save(fileName);
diff --git a/src/Avalonia.Visuals/Rendering/ImmediateRenderer.cs b/src/Avalonia.Visuals/Rendering/ImmediateRenderer.cs
index 2d5a864089..84313f0906 100644
--- a/src/Avalonia.Visuals/Rendering/ImmediateRenderer.cs
+++ b/src/Avalonia.Visuals/Rendering/ImmediateRenderer.cs
@@ -69,7 +69,7 @@ namespace Avalonia.Rendering
 
                     if (DrawFps)
                     {
-                        RenderFps(context.PlatformImpl, _root.Bounds, true);
+                        RenderFps(context.PlatformImpl, _root.Bounds, null);
                     }
                 }
             }
diff --git a/src/Avalonia.Visuals/Rendering/RendererBase.cs b/src/Avalonia.Visuals/Rendering/RendererBase.cs
index 707b31998a..eac362e997 100644
--- a/src/Avalonia.Visuals/Rendering/RendererBase.cs
+++ b/src/Avalonia.Visuals/Rendering/RendererBase.cs
@@ -22,15 +22,12 @@ namespace Avalonia.Rendering
             };
         }
 
-        protected void RenderFps(IDrawingContextImpl context, Rect clientRect, bool incrementFrameCount)
+        protected void RenderFps(IDrawingContextImpl context, Rect clientRect, int? layerCount)
         {
             var now = _stopwatch.Elapsed;
             var elapsed = now - _lastFpsUpdate;
 
-            if (incrementFrameCount)
-            {
-                ++_framesThisSecond;
-            }
+            ++_framesThisSecond;
 
             if (elapsed.TotalSeconds > 1)
             {
@@ -39,7 +36,15 @@ namespace Avalonia.Rendering
                 _lastFpsUpdate = now;
             }
 
-            _fpsText.Text = string.Format("FPS: {0:000}", _fps);
+            if (layerCount.HasValue)
+            {
+                _fpsText.Text = string.Format("Layers: {0} FPS: {1:000}", layerCount, _fps);
+            }
+            else
+            {
+                _fpsText.Text = string.Format("FPS: {0:000}", _fps);
+            }
+
             var size = _fpsText.Measure();
             var rect = new Rect(clientRect.Right - size.Width, 0, size.Width, size.Height);
 
diff --git a/src/Avalonia.Visuals/Rendering/SceneGraph/IVisualNode.cs b/src/Avalonia.Visuals/Rendering/SceneGraph/IVisualNode.cs
index 0d2fc17b95..234cadbf31 100644
--- a/src/Avalonia.Visuals/Rendering/SceneGraph/IVisualNode.cs
+++ b/src/Avalonia.Visuals/Rendering/SceneGraph/IVisualNode.cs
@@ -72,13 +72,15 @@ namespace Avalonia.Rendering.SceneGraph
         /// Sets up the drawing context for rendering the node's geometry.
         /// </summary>
         /// <param name="context">The drawing context.</param>
-        void BeginRender(IDrawingContextImpl context);
+        /// <param name="skipOpacity">Whether to skip pushing the control's opacity.</param>
+        void BeginRender(IDrawingContextImpl context, bool skipOpacity);
 
         /// <summary>
         /// Resets the drawing context after rendering the node's geometry.
         /// </summary>
         /// <param name="context">The drawing context.</param>
-        void EndRender(IDrawingContextImpl context);
+        /// <param name="skipOpacity">Whether to skip popping the control's opacity.</param>
+        void EndRender(IDrawingContextImpl context, bool skipOpacity);
 
         /// <summary>
         /// Hit test the geometry in this node.
diff --git a/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs b/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
index 90ef78de37..8f4f487e08 100644
--- a/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
+++ b/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
@@ -167,7 +167,6 @@ namespace Avalonia.Rendering.SceneGraph
                 using (context.PushPostTransform(m))
                 using (context.PushTransformContainer())
                 {
-                    var startLayer = opacity < 1 || visual.OpacityMask != null;
                     var clipBounds = bounds.TransformToAABB(contextImpl.Transform).Intersect(clip);
 
                     forceRecurse = forceRecurse ||
@@ -179,9 +178,11 @@ namespace Avalonia.Rendering.SceneGraph
                     node.ClipToBounds = clipToBounds;
                     node.GeometryClip = visual.Clip?.PlatformImpl;
                     node.Opacity = opacity;
-                    node.OpacityMask = visual.OpacityMask;
 
-                    if (startLayer)
+                    // TODO: Check equality between node.OpacityMask and visual.OpacityMask before assigning.
+                    node.OpacityMask = visual.OpacityMask?.ToImmutable();
+
+                    if (ShouldStartLayer(visual))
                     {
                         if (node.LayerRoot != visual)
                         {
@@ -192,7 +193,7 @@ namespace Avalonia.Rendering.SceneGraph
                             UpdateLayer(node, scene.Layers[node.LayerRoot]);
                         }
                     }
-                    else if (!startLayer && node.LayerRoot == node.Visual && node.Parent != null)
+                    else if (node.LayerRoot == node.Visual && node.Parent != null)
                     {
                         ClearLayer(scene, node);
                     }
@@ -366,6 +367,14 @@ namespace Avalonia.Rendering.SceneGraph
             }
         }
 
+        private static bool ShouldStartLayer(IVisual visual)
+        {
+            var o = visual as IAvaloniaObject;
+            return visual.VisualChildren.Count > 0 &&
+                o != null &&
+                o.IsAnimating(Visual.OpacityProperty);
+        }
+
         private static IGeometryImpl CreateLayerGeometryClip(VisualNode node)
         {
             IGeometryImpl result = null;
diff --git a/src/Avalonia.Visuals/Rendering/SceneGraph/VisualNode.cs b/src/Avalonia.Visuals/Rendering/SceneGraph/VisualNode.cs
index dd5740e4a9..6bea4d9bd6 100644
--- a/src/Avalonia.Visuals/Rendering/SceneGraph/VisualNode.cs
+++ b/src/Avalonia.Visuals/Rendering/SceneGraph/VisualNode.cs
@@ -22,6 +22,7 @@ namespace Avalonia.Rendering.SceneGraph
         private List<IVisualNode> _children;
         private List<IDrawOperation> _drawOperations;
         private bool _drawOperationsCloned;
+        private Matrix transformRestore;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="VisualNode"/> class.
@@ -218,8 +219,10 @@ namespace Avalonia.Rendering.SceneGraph
         }
 
         /// <inheritdoc/>
-        public void BeginRender(IDrawingContextImpl context)
+        public void BeginRender(IDrawingContextImpl context, bool skipOpacity)
         {
+            transformRestore = context.Transform;
+
             if (ClipToBounds)
             {
                 context.Transform = Matrix.Identity;
@@ -228,24 +231,47 @@ namespace Avalonia.Rendering.SceneGraph
 
             context.Transform = Transform;
 
+            if (Opacity != 1 && !skipOpacity)
+            {
+                context.PushOpacity(Opacity);
+            }
+
             if (GeometryClip != null)
             {
                 context.PushGeometryClip(GeometryClip);
             }
+
+            if (OpacityMask != null)
+            {
+                context.PushOpacityMask(OpacityMask, ClipBounds);
+            }
         }
 
         /// <inheritdoc/>
-        public void EndRender(IDrawingContextImpl context)
+        public void EndRender(IDrawingContextImpl context, bool skipOpacity)
         {
+            if (OpacityMask != null)
+            {
+                context.PopOpacityMask();
+            }
+
             if (GeometryClip != null)
             {
                 context.PopGeometryClip();
             }
 
+            if (Opacity != 1 && !skipOpacity)
+            {
+                context.PopOpacity();
+            }
+
             if (ClipToBounds)
             {
+                context.Transform = Matrix.Identity;
                 context.PopClip();
             }
+
+            context.Transform = transformRestore;
         }
 
         private Rect CalculateBounds()
diff --git a/src/Avalonia.Visuals/Visual.cs b/src/Avalonia.Visuals/Visual.cs
index bc65d4f69f..3662fe50be 100644
--- a/src/Avalonia.Visuals/Visual.cs
+++ b/src/Avalonia.Visuals/Visual.cs
@@ -537,6 +537,19 @@ namespace Avalonia
                         v.SetVisualParent(null);
                     }
 
+                    break;
+
+                case NotifyCollectionChangedAction.Replace:
+                    foreach (Visual v in e.OldItems)
+                    {
+                        v.SetVisualParent(null);
+                    }
+
+                    foreach (Visual v in e.NewItems)
+                    {
+                        v.SetVisualParent(this);
+                    }
+
                     break;
             }
         }
diff --git a/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj b/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
index a1db5c2915..0ce2a1a992 100644
--- a/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
+++ b/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
@@ -22,7 +22,7 @@
     <DefineConstants>NETSTANDARD1_3;PCL;NETSTANDARD</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Markup.Xaml.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Markup.Xaml.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
   </PropertyGroup>
     <ItemGroup>
@@ -91,6 +91,7 @@
         <Compile Include="Templates\TemplateContent.cs" />
         <Compile Include="Templates\TemplateLoader.cs" />
         <Compile Include="Templates\TreeDataTemplate.cs" />
+        <Compile Include="XamlLoadException.cs" />
         <Compile Include="PortableXaml\portable.xaml.github\src\Portable.Xaml\**\*.cs" Exclude="PortableXaml\portable.xaml.github\src\Portable.Xaml\Assembly\**\*.cs" />
         <Compile Remove="**\UriTypeConverter.cs" />
     </ItemGroup>
diff --git a/src/Markup/Avalonia.Markup.Xaml/AvaloniaXamlLoaderPortableXaml.cs b/src/Markup/Avalonia.Markup.Xaml/AvaloniaXamlLoaderPortableXaml.cs
index 0419db5d0f..de2a79c54e 100644
--- a/src/Markup/Avalonia.Markup.Xaml/AvaloniaXamlLoaderPortableXaml.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/AvaloniaXamlLoaderPortableXaml.cs
@@ -127,7 +127,19 @@ namespace Avalonia.Markup.Xaml
 
             using (var stream = assetLocator.Open(uri, baseUri))
             {
-                return Load(stream, rootInstance, uri);
+                try
+                {
+                    return Load(stream, rootInstance, uri);
+                }
+                catch (Exception e)
+                {
+                    var uriString = uri.ToString();
+                    if (!uri.IsAbsoluteUri)
+                    {
+                        uriString = new Uri(baseUri, uri).AbsoluteUri;
+                    }
+                    throw new XamlLoadException("Error loading xaml at " + uriString, e);
+                }
             }
         }
 
diff --git a/src/Markup/Avalonia.Markup.Xaml/Data/Binding.cs b/src/Markup/Avalonia.Markup.Xaml/Data/Binding.cs
index eb5f87ea2a..7f750144df 100644
--- a/src/Markup/Avalonia.Markup.Xaml/Data/Binding.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/Data/Binding.cs
@@ -66,7 +66,7 @@ namespace Avalonia.Markup.Xaml.Data
         /// <summary>
         /// Gets or sets the binding path.
         /// </summary>
-        public string Path { get; set; }
+        public string Path { get; set; } = "";
 
         /// <summary>
         /// Gets or sets the binding priority.
@@ -93,53 +93,53 @@ namespace Avalonia.Markup.Xaml.Data
             bool enableDataValidation = false)
         {
             Contract.Requires<ArgumentNullException>(target != null);
-
             anchor = anchor ?? DefaultAnchor?.Target;
-
-            var pathInfo = ParsePath(Path);
-            ValidateState(pathInfo);
+            
             enableDataValidation = enableDataValidation && Priority == BindingPriority.LocalValue;
-
+            
             ExpressionObserver observer;
 
-            if (pathInfo.ElementName != null || ElementName != null)
+            if (ElementName != null)
             {
                 observer = CreateElementObserver(
                     (target as IControl) ?? (anchor as IControl),
-                    pathInfo.ElementName ?? ElementName,
-                    pathInfo.Path);
+                    ElementName,
+                    Path,
+                    enableDataValidation);
             }
             else if (Source != null)
             {
-                observer = CreateSourceObserver(Source, pathInfo.Path, enableDataValidation);
+                observer = CreateSourceObserver(Source, Path, enableDataValidation);
             }
             else if (RelativeSource == null || RelativeSource.Mode == RelativeSourceMode.DataContext)
             {
                 observer = CreateDataContexObserver(
                     target,
-                    pathInfo.Path,
+                    Path,
                     targetProperty == Control.DataContextProperty,
                     anchor,
                     enableDataValidation);
             }
             else if (RelativeSource.Mode == RelativeSourceMode.Self)
             {
-                observer = CreateSourceObserver(target, pathInfo.Path, enableDataValidation);
+                observer = CreateSourceObserver(target, Path, enableDataValidation);
             }
             else if (RelativeSource.Mode == RelativeSourceMode.TemplatedParent)
             {
-                observer = CreateTemplatedParentObserver(target, pathInfo.Path);
+                observer = CreateTemplatedParentObserver(target, Path, enableDataValidation);
             }
             else if (RelativeSource.Mode == RelativeSourceMode.FindAncestor)
             {
-                if (RelativeSource.AncestorType == null)
+                if (RelativeSource.Tree == TreeType.Visual && RelativeSource.AncestorType == null)
                 {
-                    throw new InvalidOperationException("AncestorType must be set for RelativeSourceModel.FindAncestor.");
+                    throw new InvalidOperationException("AncestorType must be set for RelativeSourceMode.FindAncestor when searching the visual tree.");
                 }
 
                 observer = CreateFindAncestorObserver(
                     (target as IControl) ?? (anchor as IControl),
-                    pathInfo.Path);
+                    RelativeSource,
+                    Path,
+                    enableDataValidation);
             }
             else
             {
@@ -168,53 +168,6 @@ namespace Avalonia.Markup.Xaml.Data
             return new InstancedBinding(subject, Mode, Priority);
         }
 
-        private static PathInfo ParsePath(string path)
-        {
-            var result = new PathInfo();
-
-            if (string.IsNullOrWhiteSpace(path) || path == ".")
-            {
-                result.Path = string.Empty;
-            }
-            else if (path.StartsWith("#"))
-            {
-                var dot = path.IndexOf('.');
-
-                if (dot != -1)
-                {
-                    result.Path = path.Substring(dot + 1);
-                    result.ElementName = path.Substring(1, dot - 1);
-                }
-                else
-                {
-                    result.Path = string.Empty;
-                    result.ElementName = path.Substring(1);
-                }
-            }
-            else
-            {
-                result.Path = path;
-            }
-
-            return result;
-        }
-
-        private void ValidateState(PathInfo pathInfo)
-        {
-            if (pathInfo.ElementName != null && ElementName != null)
-            {
-                throw new InvalidOperationException(
-                    "ElementName property cannot be set when an #elementName path is provided.");
-            }
-
-            if ((pathInfo.ElementName != null || ElementName != null) &&
-                RelativeSource != null)
-            {
-                throw new InvalidOperationException(
-                    "ElementName property cannot be set with a RelativeSource.");
-            }
-        }
-
         private ExpressionObserver CreateDataContexObserver(
             IAvaloniaObject target,
             string path,
@@ -256,7 +209,11 @@ namespace Avalonia.Markup.Xaml.Data
             }
         }
 
-        private ExpressionObserver CreateElementObserver(IControl target, string elementName, string path)
+        private ExpressionObserver CreateElementObserver(
+            IControl target,
+            string elementName,
+            string path,
+            bool enableDataValidation)
         {
             Contract.Requires<ArgumentNullException>(target != null);
 
@@ -264,35 +221,39 @@ namespace Avalonia.Markup.Xaml.Data
             var result = new ExpressionObserver(
                 ControlLocator.Track(target, elementName),
                 path,
-                false,
+                enableDataValidation,
                 description);
             return result;
         }
 
         private ExpressionObserver CreateFindAncestorObserver(
             IControl target,
-            string path)
+            RelativeSource relativeSource,
+            string path,
+            bool enableDataValidation)
         {
             Contract.Requires<ArgumentNullException>(target != null);
 
             return new ExpressionObserver(
-                ControlLocator.Track(target, RelativeSource.AncestorType, RelativeSource.AncestorLevel -1),
-                path);
+                ControlLocator.Track(target, relativeSource.Tree, relativeSource.AncestorLevel - 1, relativeSource.AncestorType),
+                path,
+                enableDataValidation);
         }
 
         private ExpressionObserver CreateSourceObserver(
             object source,
             string path,
-            bool enabledDataValidation)
+            bool enableDataValidation)
         {
             Contract.Requires<ArgumentNullException>(source != null);
 
-            return new ExpressionObserver(source, path, enabledDataValidation);
+            return new ExpressionObserver(source, path, enableDataValidation);
         }
 
         private ExpressionObserver CreateTemplatedParentObserver(
             IAvaloniaObject target,
-            string path)
+            string path,
+            bool enableDataValidation)
         {
             Contract.Requires<ArgumentNullException>(target != null);
 
@@ -303,7 +264,8 @@ namespace Avalonia.Markup.Xaml.Data
             var result = new ExpressionObserver(
                 () => target.GetValue(Control.TemplatedParentProperty),
                 path,
-                update);
+                update,
+                enableDataValidation);
 
             return result;
         }
@@ -328,6 +290,7 @@ namespace Avalonia.Markup.Xaml.Data
         {
             public string Path { get; set; }
             public string ElementName { get; set; }
+            public RelativeSource RelativeSource { get; set; }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/Markup/Avalonia.Markup.Xaml/Data/RelativeSource.cs b/src/Markup/Avalonia.Markup.Xaml/Data/RelativeSource.cs
index f77df6853b..825d3b8ba5 100644
--- a/src/Markup/Avalonia.Markup.Xaml/Data/RelativeSource.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/Data/RelativeSource.cs
@@ -87,5 +87,7 @@ namespace Avalonia.Markup.Xaml.Data
         /// Gets or sets a value that describes the type of relative source lookup.
         /// </summary>
         public RelativeSourceMode Mode { get; set; }
+
+        public TreeType Tree { get; set; } = TreeType.Visual;
     }
 }
\ No newline at end of file
diff --git a/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/BindingExtension.cs b/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/BindingExtension.cs
index 8984498393..c6705cbb4b 100644
--- a/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/BindingExtension.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/BindingExtension.cs
@@ -29,20 +29,167 @@ namespace Avalonia.Markup.Xaml.MarkupExtensions
 
         public override object ProvideValue(IServiceProvider serviceProvider)
         {
+            var descriptorContext = (ITypeDescriptorContext)serviceProvider;
+
+            var pathInfo = ParsePath(Path, descriptorContext);
+            ValidateState(pathInfo);
+
             return new Binding
             {
                 Converter = Converter,
                 ConverterParameter = ConverterParameter,
-                ElementName = ElementName,
+                ElementName = pathInfo.ElementName ?? ElementName,
                 FallbackValue = FallbackValue,
                 Mode = Mode,
-                Path = Path,
+                Path = pathInfo.Path,
                 Priority = Priority,
-                RelativeSource = RelativeSource,
+                RelativeSource = pathInfo.RelativeSource ?? RelativeSource,
                 DefaultAnchor = new WeakReference(GetDefaultAnchor((ITypeDescriptorContext)serviceProvider))
             };
         }
 
+        private class PathInfo
+        {
+            public string Path { get; set; }
+            public string ElementName { get; set; }
+            public RelativeSource RelativeSource { get; set; }
+        }
+
+        private void ValidateState(PathInfo pathInfo)
+        {
+            if (pathInfo.ElementName != null && ElementName != null)
+            {
+                throw new InvalidOperationException(
+                    "ElementName property cannot be set when an #elementName path is provided.");
+            }
+
+            if (pathInfo.RelativeSource != null && RelativeSource != null)
+            {
+                throw new InvalidOperationException(
+                    "ElementName property cannot be set when a $self or $parent path is provided.");
+            }
+
+            if ((pathInfo.ElementName != null || ElementName != null) &&
+                (pathInfo.RelativeSource != null || RelativeSource != null))
+            {
+                throw new InvalidOperationException(
+                    "ElementName property cannot be set with a RelativeSource.");
+            }
+        }
+
+        private static PathInfo ParsePath(string path, ITypeDescriptorContext context)
+        {
+            var result = new PathInfo();
+
+            if (string.IsNullOrWhiteSpace(path) || path == ".")
+            {
+                result.Path = string.Empty;
+            }
+            else if (path.StartsWith("#"))
+            {
+                var dot = path.IndexOf('.');
+
+                if (dot != -1)
+                {
+                    result.Path = path.Substring(dot + 1);
+                    result.ElementName = path.Substring(1, dot - 1);
+                }
+                else
+                {
+                    result.Path = string.Empty;
+                    result.ElementName = path.Substring(1);
+                }
+            }
+            else if (path.StartsWith("$"))
+            {
+                var relativeSource = new RelativeSource
+                {
+                    Tree = TreeType.Logical
+                };
+                result.RelativeSource = relativeSource;
+                var dot = path.IndexOf('.');
+                string relativeSourceMode;
+                if (dot != -1)
+                {
+                    result.Path = path.Substring(dot + 1);
+                    relativeSourceMode = path.Substring(1, dot - 1);
+                }
+                else
+                {
+                    result.Path = string.Empty;
+                    relativeSourceMode = path.Substring(1);
+                }
+
+                if (relativeSourceMode == "self")
+                {
+                    relativeSource.Mode = RelativeSourceMode.Self;
+                }
+                else if (relativeSourceMode == "parent")
+                {
+                    relativeSource.Mode = RelativeSourceMode.FindAncestor;
+                    relativeSource.AncestorLevel = 1;
+                }
+                else if (relativeSourceMode.StartsWith("parent["))
+                {
+                    relativeSource.Mode = RelativeSourceMode.FindAncestor;
+                    var parentConfigStart = relativeSourceMode.IndexOf('[');
+                    if (!relativeSourceMode.EndsWith("]"))
+                    {
+                        throw new InvalidOperationException("Invalid RelativeSource binding syntax. Expected matching ']' for '['.");
+                    }
+                    var parentConfigParams = relativeSourceMode.Substring(parentConfigStart + 1).TrimEnd(']').Split(';');
+                    if (parentConfigParams.Length > 2 || parentConfigParams.Length == 0)
+                    {
+                        throw new InvalidOperationException("Expected either 1 or 2 parameters for RelativeSource binding syntax");
+                    }
+                    else if (parentConfigParams.Length == 1)
+                    {
+                        if (int.TryParse(parentConfigParams[0], out int level))
+                        {
+                            relativeSource.AncestorType = null;
+                            relativeSource.AncestorLevel = level + 1;
+                        }
+                        else
+                        {
+                            relativeSource.AncestorType = LookupAncestorType(parentConfigParams[0], context);
+                        }
+                    }
+                    else
+                    {
+                        relativeSource.AncestorType = LookupAncestorType(parentConfigParams[0], context);
+                        relativeSource.AncestorLevel = int.Parse(parentConfigParams[1]) + 1;
+                    }
+                }
+                else
+                {
+                    throw new InvalidOperationException($"Invalid RelativeSource binding syntax: {relativeSourceMode}");
+                }
+            }
+            else
+            {
+                result.Path = path;
+            }
+
+            return result;
+        }
+
+        private static Type LookupAncestorType(string ancestorTypeName, ITypeDescriptorContext context)
+        {
+            var parts = ancestorTypeName.Split(':');
+            if (parts.Length == 0 || parts.Length > 2)
+            {
+                throw new InvalidOperationException("Invalid type name");
+            }
+
+            if (parts.Length == 1)
+            {
+                return context.ResolveType(string.Empty, parts[0]);
+            }
+            else
+            {
+                return context.ResolveType(parts[0], parts[1]);
+            }
+        }
 
         private static object GetDefaultAnchor(ITypeDescriptorContext context)
         {
diff --git a/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/TemplateBindingExtension.cs b/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/TemplateBindingExtension.cs
index 4664947b8e..c5fe83977f 100644
--- a/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/TemplateBindingExtension.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/TemplateBindingExtension.cs
@@ -29,7 +29,7 @@ namespace Avalonia.Markup.Xaml.MarkupExtensions
                 ElementName = ElementName,
                 Mode = Mode,
                 RelativeSource = new RelativeSource(RelativeSourceMode.TemplatedParent),
-                Path = Path,
+                Path = Path ?? string.Empty,
                 Priority = Priority,
             };
         }
diff --git a/src/Markup/Avalonia.Markup.Xaml/PortableXaml/portable.xaml.github b/src/Markup/Avalonia.Markup.Xaml/PortableXaml/portable.xaml.github
index f226a516fe..c066401445 160000
--- a/src/Markup/Avalonia.Markup.Xaml/PortableXaml/portable.xaml.github
+++ b/src/Markup/Avalonia.Markup.Xaml/PortableXaml/portable.xaml.github
@@ -1 +1 @@
-Subproject commit f226a516fe2bc191145c1fbf732f5a087f121a33
+Subproject commit c0664014455392ac221a765e66f9837704339b6f
diff --git a/src/Markup/Avalonia.Markup.Xaml/XamlLoadException.cs b/src/Markup/Avalonia.Markup.Xaml/XamlLoadException.cs
new file mode 100644
index 0000000000..e66b8ddf54
--- /dev/null
+++ b/src/Markup/Avalonia.Markup.Xaml/XamlLoadException.cs
@@ -0,0 +1,24 @@
+using System;
+using System.Runtime.Serialization;
+
+namespace Avalonia.Markup.Xaml
+{
+    public class XamlLoadException: Exception
+    {
+        public XamlLoadException()
+        {
+        }
+
+        protected XamlLoadException(SerializationInfo info, StreamingContext context): base(info, context)
+        {
+        }
+
+        public XamlLoadException(string message): base(message)
+        {
+        }
+
+        public XamlLoadException(string message, Exception innerException): base(message, innerException)
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj b/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj
index 57552f852c..a6d3c3336f 100644
--- a/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj
+++ b/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj
@@ -11,7 +11,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Markup.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Markup.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
@@ -21,7 +21,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Markup.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Markup.xml</DocumentationFile>
     <NoWarn>CS1591</NoWarn>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
diff --git a/src/Markup/Avalonia.Markup/ControlLocator.cs b/src/Markup/Avalonia.Markup/ControlLocator.cs
index de8415d6db..1a82c0a4fd 100644
--- a/src/Markup/Avalonia.Markup/ControlLocator.cs
+++ b/src/Markup/Avalonia.Markup/ControlLocator.cs
@@ -11,6 +11,21 @@ using Avalonia.VisualTree;
 
 namespace Avalonia.Markup
 {
+    /// <summary>
+    /// The type of tree via which to track a control.
+    /// </summary>
+    public enum TreeType
+    {
+        /// <summary>
+        /// The visual tree.
+        /// </summary>
+        Visual,
+        /// <summary>
+        /// The logical tree.
+        /// </summary>
+        Logical,
+    }
+
     /// <summary>
     /// Locates controls relative to other controls.
     /// </summary>
@@ -27,13 +42,13 @@ namespace Avalonia.Markup
         {
             var attached = Observable.FromEventPattern<LogicalTreeAttachmentEventArgs>(
                 x => relativeTo.AttachedToLogicalTree += x,
-                x => relativeTo.DetachedFromLogicalTree += x)
+                x => relativeTo.AttachedToLogicalTree -= x)
                 .Select(x => ((IControl)x.Sender).FindNameScope())
                 .StartWith(relativeTo.FindNameScope());
 
             var detached = Observable.FromEventPattern<LogicalTreeAttachmentEventArgs>(
                 x => relativeTo.DetachedFromLogicalTree += x,
-                x => relativeTo.DetachedFromLogicalTree += x)
+                x => relativeTo.DetachedFromLogicalTree -= x)
                 .Select(x => (INameScope)null);
 
             return attached.Merge(detached).Select(nameScope =>
@@ -68,37 +83,75 @@ namespace Avalonia.Markup
         /// <param name="relativeTo">
         /// The control relative from which the other control should be found.
         /// </param>
-        /// <param name="ancestorType">The type of the ancestor to find.</param>
+        /// <param name="tree">The tree via which to track the control.</param>
         /// <param name="ancestorLevel">
         /// The level of ancestor control to look for. Use 0 for the first ancestor of the
         /// requested type.
         /// </param>
-        public static IObservable<IControl> Track(IControl relativeTo, Type ancestorType, int ancestorLevel)
+        /// <param name="ancestorType">The type of the ancestor to find.</param>
+        public static IObservable<IControl> Track(IControl relativeTo, TreeType tree, int ancestorLevel, Type ancestorType = null)
+        {
+            return TrackAttachmentToTree(relativeTo, tree).Select(isAttachedToTree =>
+            {
+                if (isAttachedToTree)
+                {
+                    if (tree == TreeType.Visual)
+                    {
+                        return relativeTo.GetVisualAncestors()
+                            .Where(x => ancestorType?.GetTypeInfo().IsAssignableFrom(x.GetType().GetTypeInfo()) ?? true)
+                            .ElementAtOrDefault(ancestorLevel) as IControl; 
+                    }
+                    else
+                    {
+                        return relativeTo.GetLogicalAncestors()
+                            .Where(x => ancestorType?.GetTypeInfo().IsAssignableFrom(x.GetType().GetTypeInfo()) ?? true)
+                            .ElementAtOrDefault(ancestorLevel) as IControl;
+                    }
+                }
+                else
+                {
+                    return null;
+                }
+            });
+        }
+
+        private static IObservable<bool> TrackAttachmentToTree(IControl relativeTo, TreeType tree)
+        {
+            return tree == TreeType.Visual ? TrackAttachmentToVisualTree(relativeTo) : TrackAttachmentToLogicalTree(relativeTo);
+        }
+
+        private static IObservable<bool> TrackAttachmentToVisualTree(IControl relativeTo)
         {
             var attached = Observable.FromEventPattern<VisualTreeAttachmentEventArgs>(
                 x => relativeTo.AttachedToVisualTree += x,
-                x => relativeTo.DetachedFromVisualTree += x)
+                x => relativeTo.AttachedToVisualTree -= x)
                 .Select(x => true)
                 .StartWith(relativeTo.IsAttachedToVisualTree);
 
             var detached = Observable.FromEventPattern<VisualTreeAttachmentEventArgs>(
                 x => relativeTo.DetachedFromVisualTree += x,
-                x => relativeTo.DetachedFromVisualTree += x)
+                x => relativeTo.DetachedFromVisualTree -= x)
                 .Select(x => false);
 
-            return attached.Merge(detached).Select(isAttachedToVisualTree =>
-            {
-                if (isAttachedToVisualTree)
-                {
-                    return relativeTo.GetVisualAncestors()
-                        .Where(x => ancestorType.GetTypeInfo().IsAssignableFrom(x.GetType().GetTypeInfo()))
-                        .ElementAtOrDefault(ancestorLevel) as IControl;
-                }
-                else
-                {
-                    return null;
-                }
-            });
+            var attachmentStatus = attached.Merge(detached);
+            return attachmentStatus;
+        }
+
+        private static IObservable<bool> TrackAttachmentToLogicalTree(IControl relativeTo)
+        {
+            var attached = Observable.FromEventPattern<LogicalTreeAttachmentEventArgs>(
+                x => relativeTo.AttachedToLogicalTree += x,
+                x => relativeTo.AttachedToLogicalTree -= x)
+                .Select(x => true)
+                .StartWith(relativeTo.IsAttachedToLogicalTree);
+
+            var detached = Observable.FromEventPattern<LogicalTreeAttachmentEventArgs>(
+                x => relativeTo.DetachedFromLogicalTree += x,
+                x => relativeTo.DetachedFromLogicalTree -= x)
+                .Select(x => false);
+
+            var attachmentStatus = attached.Merge(detached);
+            return attachmentStatus;
         }
     }
 }
diff --git a/src/Markup/Avalonia.Markup/Data/Parsers/ArgumentListParser.cs b/src/Markup/Avalonia.Markup/Data/Parsers/ArgumentListParser.cs
index a824a38867..563b372c78 100644
--- a/src/Markup/Avalonia.Markup/Data/Parsers/ArgumentListParser.cs
+++ b/src/Markup/Avalonia.Markup/Data/Parsers/ArgumentListParser.cs
@@ -51,15 +51,7 @@ namespace Avalonia.Markup.Data.Parsers
                     }
                 }
 
-                if (!r.End)
-                {
-                    r.Take();
-                    return result;
-                }
-                else
-                {
-                    throw new ExpressionParseException(r.Position, "Expected ']'.");
-                }
+                throw new ExpressionParseException(r.Position, "Expected ']'.");
             }
 
             return null;
diff --git a/src/Skia/Avalonia.Skia/FormattedTextImpl.cs b/src/Skia/Avalonia.Skia/FormattedTextImpl.cs
index f727d033cc..f22722a0b5 100644
--- a/src/Skia/Avalonia.Skia/FormattedTextImpl.cs
+++ b/src/Skia/Avalonia.Skia/FormattedTextImpl.cs
@@ -450,7 +450,7 @@ namespace Avalonia.Skia
                 {
                     var match = _foregroundBrushes[bi];
 
-                    len = match.Key.EndIndex - index + 1;
+                    len = match.Key.EndIndex - index;
                     result = match.Value;
 
                     if (len > 0 && len < length)
@@ -641,7 +641,7 @@ namespace Avalonia.Skia
                 Length = length;
             }
 
-            public int EndIndex => StartIndex + Length - 1;
+            public int EndIndex => StartIndex + Length;
 
             public int Length { get; private set; }
 
diff --git a/src/Windows/Avalonia.Direct2D1/Media/DrawingContextImpl.cs b/src/Windows/Avalonia.Direct2D1/Media/DrawingContextImpl.cs
index 6a72923ce3..b1bfdcbfeb 100644
--- a/src/Windows/Avalonia.Direct2D1/Media/DrawingContextImpl.cs
+++ b/src/Windows/Avalonia.Direct2D1/Media/DrawingContextImpl.cs
@@ -54,7 +54,6 @@ namespace Avalonia.Direct2D1.Media
             _finishedCallback = finishedCallback;
             _directWriteFactory = directWriteFactory;
             _imagingFactory = imagingFactory;
-            _swapChain = swapChain;
             _renderTarget.BeginDraw();
         }
 
diff --git a/src/Windows/Avalonia.Win32/Avalonia.Win32.csproj b/src/Windows/Avalonia.Win32/Avalonia.Win32.csproj
index b2b42877b7..92d973238e 100644
--- a/src/Windows/Avalonia.Win32/Avalonia.Win32.csproj
+++ b/src/Windows/Avalonia.Win32/Avalonia.Win32.csproj
@@ -22,7 +22,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Debug\Avalonia.Win32.XML</DocumentationFile>
+    <DocumentationFile>bin\Debug\Avalonia.Win32.xml</DocumentationFile>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <NoWarn>CS1591</NoWarn>
   </PropertyGroup>
@@ -33,7 +33,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>bin\Release\Avalonia.Win32.XML</DocumentationFile>
+    <DocumentationFile>bin\Release\Avalonia.Win32.xml</DocumentationFile>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <NoWarn>CS1591</NoWarn>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
diff --git a/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Binding.cs b/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Binding.cs
index 4d6559a078..c75150ca6d 100644
--- a/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Binding.cs
+++ b/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Binding.cs
@@ -2,22 +2,22 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
-using System.Collections;
-using System.Collections.Generic;
+using System.ComponentModel;
+using System.Reactive.Concurrency;
 using System.Reactive.Linq;
 using System.Reactive.Subjects;
-using Microsoft.Reactive.Testing;
+using System.Threading;
+using System.Threading.Tasks;
 using Avalonia.Data;
 using Avalonia.Logging;
-using Avalonia.UnitTests;
-using Xunit;
-using System.Threading.Tasks;
+using Avalonia.Markup.Xaml.Data;
 using Avalonia.Platform;
-using System.Threading;
-using Moq;
-using System.Reactive.Disposables;
-using System.Reactive.Concurrency;
 using Avalonia.Threading;
+using Avalonia.UnitTests;
+using Avalonia.Diagnostics;
+using Microsoft.Reactive.Testing;
+using Moq;
+using Xunit;
 
 namespace Avalonia.Base.UnitTests
 {
@@ -363,7 +363,7 @@ namespace Avalonia.Base.UnitTests
                 Assert.True(called);
             }
         }
-        
+
         [Fact]
         public async Task Bind_With_Scheduler_Executes_On_Scheduler()
         {
@@ -387,6 +387,77 @@ namespace Avalonia.Base.UnitTests
             }
         }
 
+        [Fact]
+        public void SetValue_Should_Not_Cause_StackOverflow_And_Have_Correct_Values()
+        {
+            var viewModel = new TestStackOverflowViewModel()
+            {
+                Value = 50
+            };
+
+            var target = new Class1();
+
+            target.Bind(Class1.DoubleValueProperty,
+                new Binding("Value") { Mode = BindingMode.TwoWay, Source = viewModel });
+
+            var child = new Class1();
+
+            child[!!Class1.DoubleValueProperty] = target[!!Class1.DoubleValueProperty];
+
+            Assert.Equal(1, viewModel.SetterInvokedCount);
+
+            // Issues #855 and #824 were causing a StackOverflowException at this point.
+            target.DoubleValue = 51.001;
+
+            Assert.Equal(2, viewModel.SetterInvokedCount);
+
+            double expected = 51;
+
+            Assert.Equal(expected, viewModel.Value);
+            Assert.Equal(expected, target.DoubleValue);
+            Assert.Equal(expected, child.DoubleValue);
+        }
+
+        [Fact]
+        public void IsAnimating_On_Property_With_No_Value_Returns_False()
+        {
+            var target = new Class1();
+
+            Assert.False(target.IsAnimating(Class1.FooProperty));
+        }
+
+        [Fact]
+        public void IsAnimating_On_Property_With_Animation_Value_Returns_False()
+        {
+            var target = new Class1();
+
+            target.SetValue(Class1.FooProperty, "foo", BindingPriority.Animation);
+
+            Assert.False(target.IsAnimating(Class1.FooProperty));
+        }
+
+        [Fact]
+        public void IsAnimating_On_Property_With_Non_Animation_Binding_Returns_False()
+        {
+            var target = new Class1();
+            var source = new Subject<string>();
+
+            target.Bind(Class1.FooProperty, source, BindingPriority.LocalValue);
+
+            Assert.False(target.IsAnimating(Class1.FooProperty));
+        }
+
+        [Fact]
+        public void IsAnimating_On_Property_With_Animation_Binding_Returns_True()
+        {
+            var target = new Class1();
+            var source = new BehaviorSubject<string>("foo");
+
+            target.Bind(Class1.FooProperty, source, BindingPriority.Animation);
+
+            Assert.True(target.IsAnimating(Class1.FooProperty));
+        }
+
         /// <summary>
         /// Returns an observable that returns a single value but does not complete.
         /// </summary>
@@ -405,6 +476,15 @@ namespace Avalonia.Base.UnitTests
 
             public static readonly StyledProperty<double> QuxProperty =
                 AvaloniaProperty.Register<Class1, double>("Qux", 5.6);
+
+            public static readonly StyledProperty<double> DoubleValueProperty =
+                        AvaloniaProperty.Register<Class1, double>(nameof(DoubleValue));
+
+            public double DoubleValue
+            {
+                get { return GetValue(DoubleValueProperty); }
+                set { SetValue(DoubleValueProperty, value); }
+            }
         }
 
         private class Class2 : Class1
@@ -431,5 +511,40 @@ namespace Avalonia.Base.UnitTests
                 return InstancedBinding.OneTime(_source);
             }
         }
+
+        private class TestStackOverflowViewModel : INotifyPropertyChanged
+        {
+            public int SetterInvokedCount { get; private set; }
+
+            public const int MaxInvokedCount = 1000;
+
+            private double _value;
+
+            public event PropertyChangedEventHandler PropertyChanged;
+
+            public double Value
+            {
+                get { return _value; }
+                set
+                {
+                    if (_value != value)
+                    {
+                        SetterInvokedCount++;
+                        if (SetterInvokedCount < MaxInvokedCount)
+                        {
+                            _value = (int)value;
+                            if (_value > 75) _value = 75;
+                            if (_value < 25) _value = 25;
+                        }
+                        else
+                        {
+                            _value = value;
+                        }
+
+                        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
+                    }
+                }
+            }
+        }
     }
-}
+}
\ No newline at end of file
diff --git a/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Direct.cs b/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Direct.cs
index e9cb2bf450..f415d845ce 100644
--- a/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Direct.cs
+++ b/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Direct.cs
@@ -3,11 +3,18 @@
 
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Reactive.Subjects;
+using System.Threading;
+using System.Threading.Tasks;
 using Avalonia;
 using Avalonia.Data;
 using Avalonia.Logging;
+using Avalonia.Platform;
+using Avalonia.Threading;
+using Avalonia.Markup.Xaml.Data;
 using Avalonia.UnitTests;
+using Moq;
 using Xunit;
 
 namespace Avalonia.Base.UnitTests
@@ -208,7 +215,7 @@ namespace Avalonia.Base.UnitTests
         {
             var target = new Class1();
 
-            Assert.Throws<ArgumentException>(() => 
+            Assert.Throws<ArgumentException>(() =>
                 target.SetValue(Class1.BarProperty, "newvalue"));
         }
 
@@ -217,7 +224,7 @@ namespace Avalonia.Base.UnitTests
         {
             var target = new Class1();
 
-            Assert.Throws<ArgumentException>(() => 
+            Assert.Throws<ArgumentException>(() =>
                 target.SetValue((AvaloniaProperty)Class1.BarProperty, "newvalue"));
         }
 
@@ -227,7 +234,7 @@ namespace Avalonia.Base.UnitTests
             var target = new Class1();
             var source = new Subject<string>();
 
-            Assert.Throws<ArgumentException>(() => 
+            Assert.Throws<ArgumentException>(() =>
                 target.Bind(Class1.BarProperty, source));
         }
 
@@ -411,6 +418,28 @@ namespace Avalonia.Base.UnitTests
             Assert.True(called);
         }
 
+        [Fact]
+        public async Task Bind_Executes_On_UIThread()
+        {
+            var target = new Class1();
+            var source = new Subject<object>();
+            var currentThreadId = Thread.CurrentThread.ManagedThreadId;
+
+            var threadingInterfaceMock = new Mock<IPlatformThreadingInterface>();
+            threadingInterfaceMock.SetupGet(mock => mock.CurrentThreadIsLoopThread)
+                .Returns(() => Thread.CurrentThread.ManagedThreadId == currentThreadId);
+
+            var services = new TestServices(
+                threadingInterface: threadingInterfaceMock.Object);
+
+            using (UnitTestApplication.Start(services))
+            {
+                target.Bind(Class1.FooProperty, source);
+
+                await Task.Run(() => source.OnNext("foobar"));
+            }
+        }
+
         [Fact]
         public void AddOwner_Should_Inherit_DefaultBindingMode()
         {
@@ -439,12 +468,46 @@ namespace Avalonia.Base.UnitTests
             Assert.Equal(BindingMode.OneWayToSource, bar.GetMetadata<Class2>().DefaultBindingMode);
         }
 
+        [Fact]
+        public void SetValue_Should_Not_Cause_StackOverflow_And_Have_Correct_Values()
+        {
+            var viewModel = new TestStackOverflowViewModel()
+            {
+                Value = 50
+            };
+
+            var target = new Class1();
+
+            target.Bind(Class1.DoubleValueProperty, new Binding("Value")
+                                                    {
+                                                        Mode = BindingMode.TwoWay,
+                                                        Source = viewModel
+                                                    });
+
+            var child = new Class1();
+
+            child[!!Class1.DoubleValueProperty] = target[!!Class1.DoubleValueProperty];
+
+            Assert.Equal(1, viewModel.SetterInvokedCount);
+
+            // Issues #855 and #824 were causing a StackOverflowException at this point.
+            target.DoubleValue = 51.001;
+
+            Assert.Equal(2, viewModel.SetterInvokedCount);
+
+            double expected = 51;
+
+            Assert.Equal(expected, viewModel.Value);
+            Assert.Equal(expected, target.DoubleValue);
+            Assert.Equal(expected, child.DoubleValue);
+        }
+
         private class Class1 : AvaloniaObject
         {
             public static readonly DirectProperty<Class1, string> FooProperty =
                 AvaloniaProperty.RegisterDirect<Class1, string>(
-                    "Foo", 
-                    o => o.Foo, 
+                    "Foo",
+                    o => o.Foo,
                     (o, v) => o.Foo = v,
                     unsetValue: "unset");
 
@@ -453,14 +516,21 @@ namespace Avalonia.Base.UnitTests
 
             public static readonly DirectProperty<Class1, int> BazProperty =
                 AvaloniaProperty.RegisterDirect<Class1, int>(
-                    "Bar", 
-                    o => o.Baz, 
-                    (o,v) => o.Baz = v,
+                    "Bar",
+                    o => o.Baz,
+                    (o, v) => o.Baz = v,
                     unsetValue: -1);
 
+            public static readonly DirectProperty<Class1, double> DoubleValueProperty =
+                AvaloniaProperty.RegisterDirect<Class1, double>(
+                    nameof(DoubleValue),
+                    o => o.DoubleValue,
+                    (o, v) => o.DoubleValue = v);
+
             private string _foo = "initial";
             private readonly string _bar = "bar";
             private int _baz = 5;
+            private double _doubleValue;
 
             public string Foo
             {
@@ -478,6 +548,12 @@ namespace Avalonia.Base.UnitTests
                 get { return _baz; }
                 set { SetAndRaise(BazProperty, ref _baz, value); }
             }
+
+            public double DoubleValue
+            {
+                get { return _doubleValue; }
+                set { SetAndRaise(DoubleValueProperty, ref _doubleValue, value); }
+            }
         }
 
         private class Class2 : AvaloniaObject
@@ -497,5 +573,40 @@ namespace Avalonia.Base.UnitTests
                 set { SetAndRaise(FooProperty, ref _foo, value); }
             }
         }
+
+        private class TestStackOverflowViewModel : INotifyPropertyChanged
+        {
+            public int SetterInvokedCount { get; private set; }
+
+            public const int MaxInvokedCount = 1000;
+
+            private double _value;
+
+            public event PropertyChangedEventHandler PropertyChanged;
+
+            public double Value
+            {
+                get { return _value; }
+                set
+                {
+                    if (_value != value)
+                    {
+                        SetterInvokedCount++;
+                        if (SetterInvokedCount < MaxInvokedCount)
+                        {
+                            _value = (int)value;
+                            if (_value > 75) _value = 75;
+                            if (_value < 25) _value = 25;
+                        }
+                        else
+                        {
+                            _value = value;
+                        }
+
+                        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
+                    }
+                }
+            }
+        }
     }
-}
+}
\ No newline at end of file
diff --git a/tests/Avalonia.Base.UnitTests/AvaloniaPropertyTests.cs b/tests/Avalonia.Base.UnitTests/AvaloniaPropertyTests.cs
index 28d384fabd..2933893f7a 100644
--- a/tests/Avalonia.Base.UnitTests/AvaloniaPropertyTests.cs
+++ b/tests/Avalonia.Base.UnitTests/AvaloniaPropertyTests.cs
@@ -113,8 +113,8 @@ namespace Avalonia.Base.UnitTests
         {
             var p1 = new TestProperty<string>("p1", typeof(Class1));
 
-            Assert.NotEqual(p1, null);
-            Assert.NotEqual(null, p1);
+            Assert.NotNull(p1);
+            Assert.NotNull(p1);
             Assert.False(p1 == null);
             Assert.False(null == p1);
             Assert.False(p1.Equals(null));
diff --git a/tests/Avalonia.Base.UnitTests/Collections/AvaloniaListTests.cs b/tests/Avalonia.Base.UnitTests/Collections/AvaloniaListTests.cs
index 587816b07b..fd731455d8 100644
--- a/tests/Avalonia.Base.UnitTests/Collections/AvaloniaListTests.cs
+++ b/tests/Avalonia.Base.UnitTests/Collections/AvaloniaListTests.cs
@@ -83,6 +83,28 @@ namespace Avalonia.Base.UnitTests.Collections
             Assert.Equal(new[] { 6, 7, 8, 9, 10, 1, 2, 3, 4, 5 }, target);
         }
 
+        [Fact]
+        public void MoveRange_Raises_Correct_CollectionChanged_Event()
+        {
+            var target = new AvaloniaList<int>(new[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 });
+            var raised = false;
+
+            target.CollectionChanged += (s, e) =>
+            {
+                Assert.Equal(NotifyCollectionChangedAction.Move, e.Action);
+                Assert.Equal(0, e.OldStartingIndex);
+                Assert.Equal(10, e.NewStartingIndex);
+                Assert.Equal(new[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 }, e.OldItems);
+                Assert.Equal(new[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 }, e.NewItems);
+                raised = true;
+            };
+
+            target.MoveRange(0, 9, 10);
+
+            Assert.True(raised);
+            Assert.Equal(new[] { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9 }, target);
+        }
+
         [Fact]
         public void Adding_Item_Should_Raise_CollectionChanged()
         {
diff --git a/tests/Avalonia.Base.UnitTests/DirectPropertyTests.cs b/tests/Avalonia.Base.UnitTests/DirectPropertyTests.cs
index 3a37585dc0..84ff492512 100644
--- a/tests/Avalonia.Base.UnitTests/DirectPropertyTests.cs
+++ b/tests/Avalonia.Base.UnitTests/DirectPropertyTests.cs
@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using System.Reactive.Subjects;
 using Avalonia.Data;
 using Xunit;
 
@@ -70,6 +71,17 @@ namespace Avalonia.Base.UnitTests
             Assert.Same(p1.Initialized, p2.Initialized);
         }
 
+        [Fact]
+        public void IsAnimating_On_DirectProperty_With_Binding_Returns_False()
+        {
+            var target = new Class1();
+            var source = new BehaviorSubject<string>("foo");
+
+            target.Bind(Class1.FooProperty, source, BindingPriority.Animation);
+
+            Assert.False(target.IsAnimating(Class1.FooProperty));
+        }
+
         private class Class1 : AvaloniaObject
         {
             public static readonly DirectProperty<Class1, string> FooProperty =
diff --git a/tests/Avalonia.Base.UnitTests/PriorityValueTests.cs b/tests/Avalonia.Base.UnitTests/PriorityValueTests.cs
index 7956f385e1..6ca1364f96 100644
--- a/tests/Avalonia.Base.UnitTests/PriorityValueTests.cs
+++ b/tests/Avalonia.Base.UnitTests/PriorityValueTests.cs
@@ -206,7 +206,7 @@ namespace Avalonia.Base.UnitTests
 
             Assert.Equal(2, target.GetBindings().Count());
             disposable.Dispose();
-            Assert.Equal(1, target.GetBindings().Count());
+            Assert.Single(target.GetBindings());
         }
 
         [Fact]
@@ -248,7 +248,7 @@ namespace Avalonia.Base.UnitTests
 
             Assert.Equal(2, target.GetBindings().Count());
             subject.OnCompleted();
-            Assert.Equal(1, target.GetBindings().Count());
+            Assert.Single(target.GetBindings());
         }
 
         [Fact]
diff --git a/tests/Avalonia.Benchmarks/Avalonia.Benchmarks.csproj b/tests/Avalonia.Benchmarks/Avalonia.Benchmarks.csproj
index 1d987e2238..c16b89e0b6 100644
--- a/tests/Avalonia.Benchmarks/Avalonia.Benchmarks.csproj
+++ b/tests/Avalonia.Benchmarks/Avalonia.Benchmarks.csproj
@@ -49,6 +49,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Base\Properties.cs" />
     <Compile Include="Layout\Measure.cs" />
     <Compile Include="Styling\ApplyStyling.cs" />
     <Compile Include="Program.cs" />
diff --git a/tests/Avalonia.Benchmarks/Base/Properties.cs b/tests/Avalonia.Benchmarks/Base/Properties.cs
new file mode 100644
index 0000000000..0a020961d5
--- /dev/null
+++ b/tests/Avalonia.Benchmarks/Base/Properties.cs
@@ -0,0 +1,43 @@
+using System;
+using System.Reactive.Subjects;
+using BenchmarkDotNet.Attributes;
+
+namespace Avalonia.Benchmarks.Base
+{
+    [MemoryDiagnoser]
+    public class AvaloniaObjectBenchmark
+    {
+        private Class1 target = new Class1();
+        private Subject<int> intBinding = new Subject<int>();
+
+        public AvaloniaObjectBenchmark()
+        {
+            target.SetValue(Class1.IntProperty, 123);
+        }
+
+        [Benchmark]
+        public void ClearAndSetIntProperty()
+        {
+            target.ClearValue(Class1.IntProperty);
+            target.SetValue(Class1.IntProperty, 123);
+        }
+
+        [Benchmark]
+        public void BindIntProperty()
+        {
+            using (target.Bind(Class1.IntProperty, intBinding))
+            {
+                for (var i = 0; i < 100; ++i)
+                {
+                    intBinding.OnNext(i);
+                }
+            }
+        }
+
+        class Class1 : AvaloniaObject
+        {
+            public static readonly AvaloniaProperty<int> IntProperty =
+                AvaloniaProperty.Register<Class1, int>("Int");
+        }
+    }
+}
diff --git a/tests/Avalonia.Controls.UnitTests/CalendarTests.cs b/tests/Avalonia.Controls.UnitTests/CalendarTests.cs
new file mode 100644
index 0000000000..4c45b1b230
--- /dev/null
+++ b/tests/Avalonia.Controls.UnitTests/CalendarTests.cs
@@ -0,0 +1,277 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using Xunit;
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Avalonia.Controls.UnitTests
+{
+    public class CalendarTests
+    {
+        private static bool CompareDates(DateTime first, DateTime second)
+        {
+            return first.Year == second.Year && 
+                first.Month == second.Month &&
+                first.Day == second.Day;
+        }
+
+        [Fact]
+        public void SelectedDatesChanged_Should_Fire_When_SelectedDate_Set()
+        {
+            bool handled = false;
+            Calendar calendar = new Calendar();
+            calendar.SelectionMode = CalendarSelectionMode.SingleDate;
+            calendar.SelectedDatesChanged += new EventHandler<SelectionChangedEventArgs>(delegate
+            {
+                handled = true;
+            });
+            DateTime value = new DateTime(2000, 10, 10);
+            calendar.SelectedDate = value;
+            Assert.True(handled);
+        }
+
+        [Fact]
+        public void DisplayDateChanged_Should_Fire_When_DisplayDate_Set()
+        {
+            bool handled = false;
+            Calendar calendar = new Calendar();
+            calendar.SelectionMode = CalendarSelectionMode.SingleDate;
+            calendar.DisplayDateChanged += new EventHandler<CalendarDateChangedEventArgs>(delegate
+            {
+                handled = true;
+            });
+            DateTime value = new DateTime(2000, 10, 10);
+            calendar.DisplayDate = value;
+            Assert.True(handled);
+        }
+
+        [Fact]
+        public void Setting_Selected_Date_To_Blackout_Date_Should_Throw()
+        {
+            Calendar calendar = new Calendar();
+            calendar.BlackoutDates.AddDatesInPast();
+
+            Assert.ThrowsAny<ArgumentOutOfRangeException>(
+                () => calendar.SelectedDate = DateTime.Today.AddDays(-1));
+        }
+
+        [Fact]
+        public void Setting_Selected_Date_To_Blackout_Date_Should_Throw_Range()
+        {
+            Calendar calendar = new Calendar();
+            calendar.BlackoutDates.Add(new CalendarDateRange(DateTime.Today, DateTime.Today.AddDays(10)));
+
+            calendar.SelectedDate = DateTime.Today.AddDays(-1);
+            Assert.True(CompareDates(calendar.SelectedDate.Value, DateTime.Today.AddDays(-1)));
+            Assert.True(CompareDates(calendar.SelectedDate.Value, calendar.SelectedDates[0]));
+
+            calendar.SelectedDate = DateTime.Today.AddDays(11);
+            Assert.True(CompareDates(calendar.SelectedDate.Value, DateTime.Today.AddDays(11)));
+            Assert.True(CompareDates(calendar.SelectedDate.Value, calendar.SelectedDates[0]));
+
+            Assert.ThrowsAny<ArgumentOutOfRangeException>(
+                () => calendar.SelectedDate = DateTime.Today.AddDays(5));
+        }
+
+        [Fact]
+        public void Adding_Blackout_Dates_Containing_Selected_Date_Should_Throw()
+        {
+            Calendar calendar = new Calendar();
+            calendar.SelectedDate = DateTime.Today.AddDays(5);
+
+            Assert.ThrowsAny<ArgumentOutOfRangeException>(
+                () => calendar.BlackoutDates.Add(new CalendarDateRange(DateTime.Today, DateTime.Today.AddDays(10))));
+        }
+
+        [Fact]
+        public void DisplayDateStartEnd_Should_Constrain_Display_Date()
+        {
+            Calendar calendar = new Calendar();
+            calendar.SelectionMode = CalendarSelectionMode.SingleDate;
+            calendar.DisplayDateStart = new DateTime(2005, 12, 30);
+
+            DateTime value = new DateTime(2005, 12, 15);
+            calendar.DisplayDate = value;
+            Assert.True(CompareDates(calendar.DisplayDate, calendar.DisplayDateStart.Value));
+
+            value = new DateTime(2005, 12, 30);
+            calendar.DisplayDate = value;
+            Assert.True(CompareDates(calendar.DisplayDate, value));
+
+            value = DateTime.MaxValue;
+            calendar.DisplayDate = value;
+            Assert.True(CompareDates(calendar.DisplayDate, value));
+
+            calendar.DisplayDateEnd = new DateTime(2010, 12, 30);
+            Assert.True(CompareDates(calendar.DisplayDate, calendar.DisplayDateEnd.Value));
+        }
+
+        [Fact]
+        public void Setting_DisplayDateEnd_Should_Alter_DispalyDate_And_DisplayDateStart()
+        {
+            Calendar calendar = new Calendar();
+            DateTime value = new DateTime(2000, 1, 30);
+
+            calendar.DisplayDate = value;
+            calendar.DisplayDateEnd = value;
+            calendar.DisplayDateStart = value;
+            Assert.True(CompareDates(calendar.DisplayDateStart.Value, value));
+            Assert.True(CompareDates(calendar.DisplayDateEnd.Value, value));
+
+            value = value.AddMonths(2);
+            calendar.DisplayDateStart = value;
+            Assert.True(CompareDates(calendar.DisplayDateStart.Value, value));
+            Assert.True(CompareDates(calendar.DisplayDateEnd.Value, value));
+            Assert.True(CompareDates(calendar.DisplayDate, value));
+        }
+
+        [Fact]
+        public void Display_Date_Range_End_Will_Contain_SelectedDate()
+        {
+            Calendar calendar = new Calendar();
+            calendar.SelectionMode = CalendarSelectionMode.SingleDate;
+
+            calendar.SelectedDate = DateTime.MaxValue;
+            Assert.True(CompareDates((DateTime)calendar.SelectedDate, DateTime.MaxValue));
+
+            calendar.DisplayDateEnd = DateTime.MaxValue.AddDays(-1);
+            Assert.True(CompareDates((DateTime)calendar.DisplayDateEnd, DateTime.MaxValue));
+        }
+
+
+        /// <summary>
+        /// The days added to the SelectedDates collection.
+        /// </summary>
+        private IList<object> _selectedDatesChangedAddedDays;
+
+        /// <summary>
+        /// The days removed from the SelectedDates collection.
+        /// </summary>
+        private IList<object> _selectedDateChangedRemovedDays;
+
+        /// <summary>
+        /// The number of times the SelectedDatesChanged event has been fired.
+        /// </summary>
+        private int _selectedDatesChangedCount;
+
+        /// <summary>
+        /// Handle the SelectedDatesChanged event.
+        /// </summary>
+        /// <param name="sender">The calendar.</param>
+        /// <param name="e">Event arguments.</param>
+        private void OnSelectedDatesChanged(object sender, SelectionChangedEventArgs e)
+        {
+            _selectedDatesChangedAddedDays =
+                e.AddedItems
+                 .Cast<object>()
+                 .ToList();
+            _selectedDateChangedRemovedDays = 
+                e.RemovedItems
+                 .Cast<object>()
+                 .ToList();
+            _selectedDatesChangedCount++;
+        }
+
+        /// <summary>
+        /// Clear the variables used to track the SelectedDatesChanged event.
+        /// </summary>
+        private void ResetSelectedDatesChanged()
+        {
+            if (_selectedDatesChangedAddedDays != null)
+            {
+                _selectedDatesChangedAddedDays.Clear();
+            }
+
+            if (_selectedDateChangedRemovedDays != null)
+            {
+                _selectedDateChangedRemovedDays.Clear();
+            }
+
+            _selectedDatesChangedCount = 0;
+        }
+
+        [Fact]
+        public void SingleDate_Selection_Behavior()
+        {
+            ResetSelectedDatesChanged();
+            Calendar calendar = new Calendar();
+            calendar.SelectedDatesChanged += new EventHandler<SelectionChangedEventArgs>(OnSelectedDatesChanged);
+            calendar.SelectionMode = CalendarSelectionMode.SingleDate;
+            calendar.SelectedDate = DateTime.Today;
+            Assert.True(CompareDates(calendar.SelectedDate.Value, DateTime.Today));
+            Assert.True(calendar.SelectedDates.Count == 1);
+            Assert.True(CompareDates(calendar.SelectedDates[0], DateTime.Today));
+            Assert.True(_selectedDatesChangedCount == 1);
+            Assert.True(_selectedDatesChangedAddedDays.Count == 1);
+            Assert.True(_selectedDateChangedRemovedDays.Count == 0);
+            ResetSelectedDatesChanged();
+
+            calendar.SelectedDate = DateTime.Today;
+            Assert.True(CompareDates(calendar.SelectedDate.Value, DateTime.Today));
+            Assert.True(calendar.SelectedDates.Count == 1);
+            Assert.True(CompareDates(calendar.SelectedDates[0], DateTime.Today));
+            Assert.True(_selectedDatesChangedCount == 0);
+
+            calendar.ClearValue(Calendar.SelectedDateProperty);
+
+            calendar.SelectionMode = CalendarSelectionMode.None;
+            Assert.True(calendar.SelectedDates.Count == 0);
+            Assert.Null(calendar.SelectedDate);
+
+            calendar.SelectionMode = CalendarSelectionMode.SingleDate;
+
+            calendar.SelectedDates.Add(DateTime.Today.AddDays(1));
+            Assert.True(CompareDates(calendar.SelectedDate.Value, DateTime.Today.AddDays(1)));
+            Assert.True(calendar.SelectedDates.Count == 1);
+
+            Assert.ThrowsAny<InvalidOperationException>(
+                () => calendar.SelectedDates.Add(DateTime.Today.AddDays(2)));
+        }
+
+        [Fact]
+        public void SingleRange_Selection_Behavior()
+        {
+            ResetSelectedDatesChanged();
+            Calendar calendar = new Calendar();
+            calendar.SelectedDatesChanged += new EventHandler<SelectionChangedEventArgs>(OnSelectedDatesChanged);
+            calendar.SelectionMode = CalendarSelectionMode.SingleRange;
+            calendar.SelectedDate = DateTime.Today;
+            Assert.True(CompareDates(calendar.SelectedDate.Value, DateTime.Today));
+            Assert.True(calendar.SelectedDates.Count == 1);
+            Assert.True(CompareDates(calendar.SelectedDates[0], DateTime.Today));
+            Assert.True(_selectedDatesChangedCount == 1);
+            Assert.True(_selectedDatesChangedAddedDays.Count == 1);
+            Assert.True(_selectedDateChangedRemovedDays.Count == 0);
+            ResetSelectedDatesChanged();
+
+            calendar.SelectedDates.Clear();
+            Assert.Null(calendar.SelectedDate);
+            ResetSelectedDatesChanged();
+
+            calendar.SelectedDates.AddRange(DateTime.Today, DateTime.Today.AddDays(10));
+            Assert.True(CompareDates(calendar.SelectedDate.Value, DateTime.Today));
+            Assert.True(calendar.SelectedDates.Count == 11);
+            ResetSelectedDatesChanged();
+
+            calendar.SelectedDates.AddRange(DateTime.Today, DateTime.Today.AddDays(10));
+            Assert.True(calendar.SelectedDates.Count == 11);
+            Assert.True(_selectedDatesChangedCount == 0);
+            ResetSelectedDatesChanged();
+
+            calendar.SelectedDates.AddRange(DateTime.Today.AddDays(-20), DateTime.Today);
+            Assert.True(CompareDates(calendar.SelectedDate.Value, DateTime.Today.AddDays(-20)));
+            Assert.True(calendar.SelectedDates.Count == 21);
+            Assert.True(_selectedDatesChangedCount == 1);
+            Assert.True(_selectedDatesChangedAddedDays.Count == 21);
+            Assert.True(_selectedDateChangedRemovedDays.Count == 11);
+            ResetSelectedDatesChanged();
+
+            calendar.SelectedDates.Add(DateTime.Today.AddDays(100));
+            Assert.True(CompareDates(calendar.SelectedDate.Value, DateTime.Today.AddDays(100)));
+            Assert.True(calendar.SelectedDates.Count == 1);
+        }
+    }
+}
diff --git a/tests/Avalonia.Controls.UnitTests/CarouselTests.cs b/tests/Avalonia.Controls.UnitTests/CarouselTests.cs
index e91ab02327..4ce83056c6 100644
--- a/tests/Avalonia.Controls.UnitTests/CarouselTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/CarouselTests.cs
@@ -47,7 +47,7 @@ namespace Avalonia.Controls.UnitTests
             target.ApplyTemplate();
             target.Presenter.ApplyTemplate();
 
-            Assert.Equal(1, target.GetLogicalChildren().Count());
+            Assert.Single(target.GetLogicalChildren());
 
             var child = target.GetLogicalChildren().Single();
             
@@ -69,9 +69,9 @@ namespace Avalonia.Controls.UnitTests
             target.ApplyTemplate();
             target.Presenter.ApplyTemplate();
 
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
+            Assert.Single(target.ItemContainerGenerator.Containers);
             target.SelectedIndex = 1;
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
+            Assert.Single(target.ItemContainerGenerator.Containers);
         }
 
         [Fact]
@@ -88,7 +88,7 @@ namespace Avalonia.Controls.UnitTests
             target.ApplyTemplate();
             target.Presenter.ApplyTemplate();
 
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
+            Assert.Single(target.ItemContainerGenerator.Containers);
             target.SelectedIndex = 1;
             Assert.Equal(2, target.ItemContainerGenerator.Containers.Count());
         }
diff --git a/tests/Avalonia.Controls.UnitTests/ClassesTests.cs b/tests/Avalonia.Controls.UnitTests/ClassesTests.cs
index c9b9d9f82c..8d2e23d027 100644
--- a/tests/Avalonia.Controls.UnitTests/ClassesTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ClassesTests.cs
@@ -161,5 +161,15 @@ namespace Avalonia.Controls.UnitTests
 
             Assert.Equal(new[] { ":baz" }, target);
         }
+
+        [Fact]
+        public void RemoveAll_Should_Remove_Classes()
+        {
+            var target = new Classes("foo", "bar", "baz");
+
+            target.RemoveAll(new[] { "bar", "baz" });
+
+            Assert.Equal(new[] { "foo" }, target);
+        }
     }
 }
diff --git a/tests/Avalonia.Controls.UnitTests/ContentControlTests.cs b/tests/Avalonia.Controls.UnitTests/ContentControlTests.cs
index 5f86b9878d..653ab17b63 100644
--- a/tests/Avalonia.Controls.UnitTests/ContentControlTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ContentControlTests.cs
@@ -1,6 +1,7 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
+using System;
 using System.Collections.Specialized;
 using System.Linq;
 using Moq;
@@ -11,6 +12,9 @@ using Avalonia.Styling;
 using Avalonia.UnitTests;
 using Avalonia.VisualTree;
 using Xunit;
+using Avalonia.Markup.Xaml.Data;
+using Avalonia.Data;
+using System.Collections.Generic;
 
 namespace Avalonia.Controls.UnitTests
 {
@@ -273,6 +277,60 @@ namespace Avalonia.Controls.UnitTests
             Assert.Null(target.Presenter.Child.DataContext);
         }
 
+        [Fact]
+        public void Binding_ContentTemplate_After_Content_Does_Not_Leave_Orpaned_TextBlock()
+        {
+            // Test for #1271.
+            var children = new List<IControl>();
+            var presenter = new ContentPresenter();
+
+            // The content and then the content template property need to be bound with delayed bindings
+            // as they are in Avalonia.Markup.Xaml.
+            DelayedBinding.Add(presenter, ContentPresenter.ContentProperty, new Binding("Content")
+            {
+                Priority = BindingPriority.TemplatedParent,
+                RelativeSource = new RelativeSource(RelativeSourceMode.TemplatedParent),
+            });
+
+            DelayedBinding.Add(presenter, ContentPresenter.ContentTemplateProperty, new Binding("ContentTemplate")
+            {
+                Priority = BindingPriority.TemplatedParent,
+                RelativeSource = new RelativeSource(RelativeSourceMode.TemplatedParent),
+            });
+
+            presenter.GetObservable(ContentPresenter.ChildProperty).Subscribe(children.Add);
+
+            var target = new ContentControl
+            {
+                Template = new FuncControlTemplate<ContentControl>(_ => presenter),
+                ContentTemplate = new FuncDataTemplate<string>(x => new Canvas()),
+                Content = "foo",
+            };
+                        
+            // The control must be rooted.
+            var root = new TestRoot
+            {
+                Child = target,
+            };
+
+            target.ApplyTemplate();
+
+            // When the template is applied, the Content property is bound before the ContentTemplate
+            // property, causing a TextBlock to be created by the default template before ContentTemplate
+            // is bound.
+            Assert.Collection(
+                children,
+                x => Assert.Null(x),
+                x => Assert.IsType<TextBlock>(x),
+                x => Assert.IsType<Canvas>(x));
+
+            var textBlock = (TextBlock)children[1];
+
+            // The leak in #1271 was caused by the TextBlock's logical parent not being cleared when
+            // it is replaced by the Canvas.
+            Assert.Null(textBlock.GetLogicalParent());
+        }
+
         private FuncControlTemplate GetTemplate()
         {
             return new FuncControlTemplate<ContentControl>(parent =>
diff --git a/tests/Avalonia.Controls.UnitTests/ControlTests.cs b/tests/Avalonia.Controls.UnitTests/ControlTests.cs
index 3506a1606b..313c0b1253 100644
--- a/tests/Avalonia.Controls.UnitTests/ControlTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ControlTests.cs
@@ -19,7 +19,7 @@ namespace Avalonia.Controls.UnitTests
         {
             var target = new Control();
 
-            Assert.Equal(0, target.Classes.Count);
+            Assert.Empty(target.Classes);
         }
 
         [Fact]
diff --git a/tests/Avalonia.Controls.UnitTests/ControlTests_Resources.cs b/tests/Avalonia.Controls.UnitTests/ControlTests_Resources.cs
index 6a6cb48001..9ee6e3e456 100644
--- a/tests/Avalonia.Controls.UnitTests/ControlTests_Resources.cs
+++ b/tests/Avalonia.Controls.UnitTests/ControlTests_Resources.cs
@@ -168,7 +168,7 @@ namespace Avalonia.Controls.UnitTests
             target.Resources.Add("foo", "bar");
 
             Assert.True(raisedOnTarget);
-            Assert.False(raisedOnPresenter);
+            Assert.True(raisedOnPresenter);
             Assert.True(raisedOnChild);
         }
 
@@ -204,6 +204,22 @@ namespace Avalonia.Controls.UnitTests
             Assert.True(raised);
         }
 
+        [Fact]
+        public void Setting_Logical_Parent_Subscribes_To_Parents_ResourceChanged_Event()
+        {
+            var parent = new ContentControl();
+            var child = new Border();
+
+            ((ISetLogicalParent)child).SetParent(parent);
+            var raisedOnChild = false;
+
+            child.ResourcesChanged += (_, __) => raisedOnChild = true;
+
+            parent.Resources.Add("foo", "bar");
+
+            Assert.True(raisedOnChild);
+        }
+
         private IControlTemplate ContentControlTemplate()
         {
             return new FuncControlTemplate<ContentControl>(x =>
diff --git a/tests/Avalonia.Controls.UnitTests/DockPanelTests.cs b/tests/Avalonia.Controls.UnitTests/DockPanelTests.cs
index db4c3c0eca..3de67839a7 100644
--- a/tests/Avalonia.Controls.UnitTests/DockPanelTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/DockPanelTests.cs
@@ -12,7 +12,7 @@ namespace Avalonia.Controls.UnitTests
         {
             var target = new DockPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new Border { Width = 500, Height = 50, [DockPanel.DockProperty] = Dock.Top },
                     new Border { Width = 500, Height = 50, [DockPanel.DockProperty] = Dock.Bottom },
@@ -38,7 +38,7 @@ namespace Avalonia.Controls.UnitTests
         {
             var target = new DockPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new Border { Width = 50, Height = 400, [DockPanel.DockProperty] = Dock.Left },
                     new Border { Width = 50, Height = 400, [DockPanel.DockProperty] = Dock.Right },
diff --git a/tests/Avalonia.Controls.UnitTests/DropDownTests.cs b/tests/Avalonia.Controls.UnitTests/DropDownTests.cs
index b5de8c67fa..29e60a8f83 100644
--- a/tests/Avalonia.Controls.UnitTests/DropDownTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/DropDownTests.cs
@@ -89,7 +89,7 @@ namespace Avalonia.Controls.UnitTests
                 return new Panel
                 {
                     Name = "container",
-                    Children = new Controls
+                    Children =
                     {
                         new ContentControl
                         {
diff --git a/tests/Avalonia.Controls.UnitTests/GridSplitterTests.cs b/tests/Avalonia.Controls.UnitTests/GridSplitterTests.cs
index 5d622a5fc1..a1ba608ec6 100644
--- a/tests/Avalonia.Controls.UnitTests/GridSplitterTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/GridSplitterTests.cs
@@ -22,14 +22,14 @@ namespace Avalonia.Controls.UnitTests
         {
             var grid = new Grid()
                        {
-                           RowDefinitions = new RowDefinitions("*,Auto,*"),
-                           ColumnDefinitions = new ColumnDefinitions("*,*"),
-                           Children = new Controls()
-                                      {
-                                          new Border { [Grid.RowProperty] = 0 },
-                                          new GridSplitter { [Grid.RowProperty] = 1, Name = "splitter" },
-                                          new Border { [Grid.RowProperty] = 2 }
-                                      }
+                            RowDefinitions = new RowDefinitions("*,Auto,*"),
+                            ColumnDefinitions = new ColumnDefinitions("*,*"),
+                            Children =
+                            {
+                                new Border { [Grid.RowProperty] = 0 },
+                                new GridSplitter { [Grid.RowProperty] = 1, Name = "splitter" },
+                                new Border { [Grid.RowProperty] = 2 }
+                            }
                        };
 
             var root = new TestRoot { Child = grid };
@@ -43,14 +43,14 @@ namespace Avalonia.Controls.UnitTests
         {
             var grid = new Grid()
                        {
-                           ColumnDefinitions = new ColumnDefinitions("*,Auto,*"),
-                           RowDefinitions = new RowDefinitions("*,*"),
-                           Children = new Controls()
-                                      {
-                                          new Border { [Grid.ColumnProperty] = 0 },
-                                          new GridSplitter { [Grid.ColumnProperty] = 1, Name = "splitter" },
-                                          new Border { [Grid.ColumnProperty] = 2 },
-                                      }
+                            ColumnDefinitions = new ColumnDefinitions("*,Auto,*"),
+                            RowDefinitions = new RowDefinitions("*,*"),
+                            Children =
+                            {
+                                new Border { [Grid.ColumnProperty] = 0 },
+                                new GridSplitter { [Grid.ColumnProperty] = 1, Name = "splitter" },
+                                new Border { [Grid.ColumnProperty] = 2 },
+                            }
                        };
 
             var root = new TestRoot { Child = grid };
@@ -64,14 +64,14 @@ namespace Avalonia.Controls.UnitTests
         {
             var grid = new Grid()
                        {
-                           ColumnDefinitions = new ColumnDefinitions("Auto,Auto,Auto"),
-                           RowDefinitions = new RowDefinitions("Auto,Auto"),
-                           Children = new Controls()
-                                      {
-                                          new Border { [Grid.ColumnProperty] = 0 },
-                                          new GridSplitter { [Grid.ColumnProperty] = 1, Name = "splitter" },
-                                          new Border { [Grid.ColumnProperty] = 2 },
-                                      }
+                            ColumnDefinitions = new ColumnDefinitions("Auto,Auto,Auto"),
+                            RowDefinitions = new RowDefinitions("Auto,Auto"),
+                            Children =
+                            {
+                                new Border { [Grid.ColumnProperty] = 0 },
+                                new GridSplitter { [Grid.ColumnProperty] = 1, Name = "splitter" },
+                                new Border { [Grid.ColumnProperty] = 2 },
+                            }
                        };
 
             var root = new TestRoot { Child = grid };
@@ -99,11 +99,11 @@ namespace Avalonia.Controls.UnitTests
 
             var grid = new Grid()
                        {
-                           RowDefinitions = rowDefinitions,
-                           Children = new Controls()
-                                      {
-                                          control1, splitter, control2
-                                      }
+                            RowDefinitions = rowDefinitions,
+                            Children =
+                            {
+                                control1, splitter, control2
+                            }
                        };
 
             var root = new TestRoot { Child = grid };
@@ -131,14 +131,14 @@ namespace Avalonia.Controls.UnitTests
         {
             var grid = new Grid()
                        {
-                           ColumnDefinitions = new ColumnDefinitions("Auto,*,*"),
-                           RowDefinitions = new RowDefinitions("*,*"),
-                           Children = new Controls()
-                                      {
-                                          new GridSplitter { [Grid.ColumnProperty] = 0, Name = "splitter" },
-                                          new Border { [Grid.ColumnProperty] = 1 },
-                                          new Border { [Grid.ColumnProperty] = 2 },
-                                      }
+                            ColumnDefinitions = new ColumnDefinitions("Auto,*,*"),
+                            RowDefinitions = new RowDefinitions("*,*"),
+                            Children =
+                            {
+                                new GridSplitter { [Grid.ColumnProperty] = 0, Name = "splitter" },
+                                new Border { [Grid.ColumnProperty] = 1 },
+                                new Border { [Grid.ColumnProperty] = 2 },
+                            }
                        };
 
             var root = new TestRoot { Child = grid };
@@ -171,11 +171,11 @@ namespace Avalonia.Controls.UnitTests
 
             var grid = new Grid()
                        {
-                           ColumnDefinitions = columnDefinitions,
-                           Children = new Controls()
-                                      {
-                                          control1, splitter, control2
-                                      }
+                            ColumnDefinitions = columnDefinitions,
+                            Children =
+                            {
+                                control1, splitter, control2
+                            }
                        };
 
             var root = new TestRoot { Child = grid };
diff --git a/tests/Avalonia.Controls.UnitTests/GridTests.cs b/tests/Avalonia.Controls.UnitTests/GridTests.cs
index a10bb38322..c5aea6501f 100644
--- a/tests/Avalonia.Controls.UnitTests/GridTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/GridTests.cs
@@ -24,7 +24,7 @@ namespace Avalonia.Controls.UnitTests
                     new RowDefinition(GridLength.Auto),
                     new RowDefinition(GridLength.Auto),
                 },
-                Children = new Controls
+                Children =
                 {
                     new Border
                     {
diff --git a/tests/Avalonia.Controls.UnitTests/ItemsControlTests.cs b/tests/Avalonia.Controls.UnitTests/ItemsControlTests.cs
index f01eecf647..50610cf595 100644
--- a/tests/Avalonia.Controls.UnitTests/ItemsControlTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ItemsControlTests.cs
@@ -323,7 +323,7 @@ namespace Avalonia.Controls.UnitTests
                 Template = GetTemplate(),
             };
 
-            Assert.True(target.Classes.Contains(":empty"));
+            Assert.Contains(":empty", target.Classes);
         }
 
         [Fact]
@@ -335,7 +335,7 @@ namespace Avalonia.Controls.UnitTests
                 Items = new[] { 1, 2, 3 },
             };
 
-            Assert.False(target.Classes.Contains(":empty"));
+            Assert.DoesNotContain(":empty", target.Classes);
         }
 
         [Fact]
@@ -349,7 +349,7 @@ namespace Avalonia.Controls.UnitTests
 
             target.Items = new int[0];
 
-            Assert.True(target.Classes.Contains(":empty"));
+            Assert.Contains(":empty", target.Classes);
         }
 
         [Fact]
diff --git a/tests/Avalonia.Controls.UnitTests/ListBoxTests_Single.cs b/tests/Avalonia.Controls.UnitTests/ListBoxTests_Single.cs
index c7992fe80f..fee4994ee3 100644
--- a/tests/Avalonia.Controls.UnitTests/ListBoxTests_Single.cs
+++ b/tests/Avalonia.Controls.UnitTests/ListBoxTests_Single.cs
@@ -1,11 +1,15 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
+using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Templates;
+using Avalonia.Data;
 using Avalonia.Input;
 using Avalonia.LogicalTree;
+using Avalonia.Markup.Xaml.Data;
 using Avalonia.Styling;
 using Avalonia.VisualTree;
 using Xunit;
@@ -199,6 +203,71 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(1, target.SelectedIndex);
         }
 
+        [Fact]
+        public void SelectedItem_Should_Not_Cause_StackOverflow()
+        {
+            var viewModel = new TestStackOverflowViewModel()
+            {
+                Items = new List<string> { "foo", "bar", "baz" }
+            };
+
+            var target = new ListBox
+            {
+                Template = new FuncControlTemplate(CreateListBoxTemplate),
+                DataContext = viewModel,
+                Items = viewModel.Items
+            };
+
+            target.Bind(ListBox.SelectedItemProperty,
+                new Binding("SelectedItem") { Mode = BindingMode.TwoWay });
+
+            Assert.Equal(0, viewModel.SetterInvokedCount);
+
+            // In Issue #855, a Stackoverflow occured here.
+            target.SelectedItem = viewModel.Items[2];
+
+            Assert.Equal(viewModel.Items[1], target.SelectedItem);
+            Assert.Equal(1, viewModel.SetterInvokedCount);
+        }
+
+        private class TestStackOverflowViewModel : INotifyPropertyChanged
+        {
+            public List<string> Items { get; set; }
+
+            public int SetterInvokedCount { get; private set; }
+
+            public const int MaxInvokedCount = 1000;
+
+            private string _selectedItem;
+
+            public event PropertyChangedEventHandler PropertyChanged;
+
+            public string SelectedItem
+            {
+                get { return _selectedItem; }
+                set
+                {
+                    if (_selectedItem != value)
+                    {
+                        SetterInvokedCount++;
+
+                        int index = Items.IndexOf(value);
+
+                        if (MaxInvokedCount > SetterInvokedCount && index > 0)
+                        {
+                            _selectedItem = Items[index - 1];
+                        }
+                        else
+                        {
+                            _selectedItem = value;
+                        }
+
+                        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(SelectedItem)));
+                    }
+                }
+            }
+        }
+
         private Control CreateListBoxTemplate(ITemplatedControl parent)
         {
             return new ScrollViewer
@@ -237,4 +306,4 @@ namespace Avalonia.Controls.UnitTests
             target.Presenter.ApplyTemplate();
         }
     }
-}
+}
\ No newline at end of file
diff --git a/tests/Avalonia.Controls.UnitTests/PanelTests.cs b/tests/Avalonia.Controls.UnitTests/PanelTests.cs
index fb1ae3ba1a..ed239120d6 100644
--- a/tests/Avalonia.Controls.UnitTests/PanelTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/PanelTests.cs
@@ -2,8 +2,8 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System.Linq;
-using Avalonia.Collections;
 using Avalonia.LogicalTree;
+using Avalonia.VisualTree;
 using Xunit;
 
 namespace Avalonia.Controls.UnitTests
@@ -18,20 +18,9 @@ namespace Avalonia.Controls.UnitTests
 
             panel.Children.Add(child);
 
-            Assert.Equal(child.Parent, panel);
-            Assert.Equal(child.GetLogicalParent(), panel);
-        }
-
-        [Fact]
-        public void Setting_Controls_Should_Set_Child_Controls_Parent()
-        {
-            var panel = new Panel();
-            var child = new Control();
-
-            panel.Children = new Controls { child };
-
-            Assert.Equal(child.Parent, panel);
-            Assert.Equal(child.GetLogicalParent(), panel);
+            Assert.Same(child.Parent, panel);
+            Assert.Same(child.GetLogicalParent(), panel);
+            Assert.Same(child.GetVisualParent(), panel);
         }
 
         [Fact]
@@ -45,6 +34,7 @@ namespace Avalonia.Controls.UnitTests
 
             Assert.Null(child.Parent);
             Assert.Null(child.GetLogicalParent());
+            Assert.Null(child.GetVisualParent());
         }
 
         [Fact]
@@ -60,62 +50,70 @@ namespace Avalonia.Controls.UnitTests
 
             Assert.Null(child1.Parent);
             Assert.Null(child1.GetLogicalParent());
+            Assert.Null(child1.GetVisualParent());
             Assert.Null(child2.Parent);
             Assert.Null(child2.GetLogicalParent());
+            Assert.Null(child2.GetVisualParent());
         }
 
         [Fact]
-        public void Resetting_Panel_Children_Should_Clear_Child_Controls_Parent()
+        public void Replacing_Panel_Children_Should_Clear_And_Set_Control_Parent()
         {
             var panel = new Panel();
             var child1 = new Control();
             var child2 = new Control();
 
             panel.Children.Add(child1);
-            panel.Children.Add(child2);
-            panel.Children = new Controls();
+            panel.Children[0] = child2;
 
             Assert.Null(child1.Parent);
             Assert.Null(child1.GetLogicalParent());
-            Assert.Null(child2.Parent);
-            Assert.Null(child2.GetLogicalParent());
+            Assert.Null(child1.GetVisualParent());
+            Assert.Same(child2.Parent, panel);
+            Assert.Same(child2.GetLogicalParent(), panel);
+            Assert.Same(child2.GetVisualParent(), panel);
         }
 
         [Fact]
-        public void Setting_Children_Should_Make_Controls_Appear_In_Panel_Children()
+        public void Child_Control_Should_Appear_In_Panel_Logical_And_Visual_Children()
         {
             var panel = new Panel();
             var child = new Control();
 
-            panel.Children = new Controls { child };
+            panel.Children.Add(child);
 
             Assert.Equal(new[] { child }, panel.Children);
             Assert.Equal(new[] { child }, panel.GetLogicalChildren());
+            Assert.Equal(new[] { child }, panel.GetVisualChildren());
         }
 
         [Fact]
-        public void Child_Control_Should_Appear_In_Panel_Children()
+        public void Removing_Child_Control_Should_Remove_From_Panel_Logical_And_Visual_Children()
         {
             var panel = new Panel();
             var child = new Control();
 
             panel.Children.Add(child);
+            panel.Children.Remove(child);
 
-            Assert.Equal(new[] { child }, panel.Children);
-            Assert.Equal(new[] { child }, panel.GetLogicalChildren());
+            Assert.Equal(new Control[0], panel.Children);
+            Assert.Empty(panel.GetLogicalChildren());
+            Assert.Empty(panel.GetVisualChildren());
         }
 
         [Fact]
-        public void Removing_Child_Control_Should_Remove_From_Panel_Children()
+        public void Moving_Panel_Children_Should_Reoder_Logical_And_Visual_Children()
         {
             var panel = new Panel();
-            var child = new Control();
+            var child1 = new Control();
+            var child2 = new Control();
 
-            panel.Children.Add(child);
-            panel.Children.Remove(child);
+            panel.Children.Add(child1);
+            panel.Children.Add(child2);
+            panel.Children.Move(1, 0);
 
-            Assert.Equal(new Control[0], panel.Children);
-            Assert.Equal(new ILogical[0], panel.GetLogicalChildren());
+            Assert.Equal(new[] { child2, child1 }, panel.GetLogicalChildren());
+            Assert.Equal(new[] { child2, child1 }, panel.GetVisualChildren());
         }
     }
 }
diff --git a/tests/Avalonia.Controls.UnitTests/Presenters/CarouselPresenterTests.cs b/tests/Avalonia.Controls.UnitTests/Presenters/CarouselPresenterTests.cs
index 260c070406..a50fe852c3 100644
--- a/tests/Avalonia.Controls.UnitTests/Presenters/CarouselPresenterTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Presenters/CarouselPresenterTests.cs
@@ -91,9 +91,9 @@ namespace Avalonia.Controls.UnitTests.Presenters
             };
 
             target.ApplyTemplate();
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
+            Assert.Single(target.ItemContainerGenerator.Containers);
             target.SelectedIndex = 1;
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
+            Assert.Single(target.ItemContainerGenerator.Containers);
         }
 
         [Fact]
@@ -107,8 +107,8 @@ namespace Avalonia.Controls.UnitTests.Presenters
             };
 
             target.ApplyTemplate();
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
-            Assert.Equal(1, target.Panel.Children.Count);
+            Assert.Single(target.ItemContainerGenerator.Containers);
+            Assert.Single(target.Panel.Children);
             target.SelectedIndex = 1;
             Assert.Equal(2, target.ItemContainerGenerator.Containers.Count());
             Assert.Equal(2, target.Panel.Children.Count);
@@ -134,24 +134,24 @@ namespace Avalonia.Controls.UnitTests.Presenters
             items.Add("foo");
             target.SelectedIndex = 0;
 
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
-            Assert.Equal(1, target.Panel.Children.Count);
+            Assert.Single(target.ItemContainerGenerator.Containers);
+            Assert.Single(target.Panel.Children);
 
             items.Add("bar");
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
-            Assert.Equal(1, target.Panel.Children.Count);
+            Assert.Single(target.ItemContainerGenerator.Containers);
+            Assert.Single(target.Panel.Children);
 
             target.SelectedIndex = 1;
             Assert.Equal(2, target.ItemContainerGenerator.Containers.Count());
             Assert.Equal(2, target.Panel.Children.Count);            
 
             items.Remove(items[0]);
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
-            Assert.Equal(1, target.Panel.Children.Count);            
+            Assert.Single(target.ItemContainerGenerator.Containers);
+            Assert.Single(target.Panel.Children);            
 
             items.Remove(items[0]);
-            Assert.Equal(0, target.ItemContainerGenerator.Containers.Count());
-            Assert.Equal(0, target.Panel.Children.Count);            
+            Assert.Empty(target.ItemContainerGenerator.Containers);
+            Assert.Empty(target.Panel.Children);            
         }
 
         [Fact]
@@ -171,12 +171,12 @@ namespace Avalonia.Controls.UnitTests.Presenters
             items.Add("foo");
             target.SelectedIndex = 0;
 
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
-            Assert.Equal(1, target.Panel.Children.Count);
+            Assert.Single(target.ItemContainerGenerator.Containers);
+            Assert.Single(target.Panel.Children);
 
             items.Add("bar");
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
-            Assert.Equal(1, target.Panel.Children.Count);
+            Assert.Single(target.ItemContainerGenerator.Containers);
+            Assert.Single(target.Panel.Children);
 
             target.SelectedIndex = 1;
             Assert.Equal(2, target.ItemContainerGenerator.Containers.Count());
@@ -184,13 +184,13 @@ namespace Avalonia.Controls.UnitTests.Presenters
             Assert.Equal(0, target.ItemContainerGenerator.Containers.First().Index);
 
             items.Remove(items[0]);
-            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
-            Assert.Equal(1, target.Panel.Children.Count);
+            Assert.Single(target.ItemContainerGenerator.Containers);
+            Assert.Single(target.Panel.Children);
             Assert.Equal(0, target.ItemContainerGenerator.Containers.First().Index);
 
             items.Remove(items[0]);
-            Assert.Equal(0, target.ItemContainerGenerator.Containers.Count());
-            Assert.Equal(0, target.Panel.Children.Count);            
+            Assert.Empty(target.ItemContainerGenerator.Containers);
+            Assert.Empty(target.Panel.Children);            
         }
 
         private class TestItem : ContentControl
diff --git a/tests/Avalonia.Controls.UnitTests/Presenters/ContentPresenterTests_Standalone.cs b/tests/Avalonia.Controls.UnitTests/Presenters/ContentPresenterTests_Standalone.cs
index 027e162877..6716456c78 100644
--- a/tests/Avalonia.Controls.UnitTests/Presenters/ContentPresenterTests_Standalone.cs
+++ b/tests/Avalonia.Controls.UnitTests/Presenters/ContentPresenterTests_Standalone.cs
@@ -42,7 +42,7 @@ namespace Avalonia.Controls.UnitTests.Presenters
 
             var logicalChildren = target.GetLogicalChildren();
 
-            Assert.Equal(1, logicalChildren.Count());
+            Assert.Single(logicalChildren);
             Assert.Equal(content, logicalChildren.First());
         }
 
@@ -190,7 +190,7 @@ namespace Avalonia.Controls.UnitTests.Presenters
 
             var logicalChildren = target.GetLogicalChildren();
 
-            Assert.Equal(1, logicalChildren.Count());
+            Assert.Single(logicalChildren);
 
             target.Content = "bar";
             target.UpdateChild();
@@ -199,7 +199,7 @@ namespace Avalonia.Controls.UnitTests.Presenters
 
             logicalChildren = target.GetLogicalChildren();
 
-            Assert.Equal(1, logicalChildren.Count());
+            Assert.Single(logicalChildren);
             Assert.NotEqual(foo, logicalChildren.First());
         }
 
diff --git a/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests.cs b/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests.cs
index ef7e1062ec..048cdb2ccb 100644
--- a/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests.cs
@@ -87,7 +87,7 @@ namespace Avalonia.Controls.UnitTests.Presenters
             target.ApplyTemplate();
             items.RemoveAt(0);
 
-            Assert.Equal(1, target.Panel.Children.Count);
+            Assert.Single(target.Panel.Children);
             Assert.Equal("bar", ((ContentPresenter)target.Panel.Children[0]).Content);
             Assert.Equal("bar", ((ContentPresenter)target.ItemContainerGenerator.ContainerFromIndex(0)).Content);
         }
diff --git a/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests_Virtualization_Simple.cs b/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests_Virtualization_Simple.cs
index 51433cc08e..80cc13ab78 100644
--- a/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests_Virtualization_Simple.cs
+++ b/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests_Virtualization_Simple.cs
@@ -704,7 +704,7 @@ namespace Avalonia.Controls.UnitTests.Presenters
             target.Measure(new Size(100, 100));
             target.Arrange(new Rect(target.DesiredSize));
 
-            Assert.Equal(0, target.Panel.Children.Count);
+            Assert.Empty(target.Panel.Children);
 
             items.AddRange(defaultItems.Select(s => s + " new"));
 
diff --git a/tests/Avalonia.Controls.UnitTests/Primitives/PopupRootTests.cs b/tests/Avalonia.Controls.UnitTests/Primitives/PopupRootTests.cs
index 64344a1584..d4b5d01a6b 100644
--- a/tests/Avalonia.Controls.UnitTests/Primitives/PopupRootTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Primitives/PopupRootTests.cs
@@ -2,11 +2,14 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using System.Linq;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
 using Avalonia.LogicalTree;
+using Avalonia.Styling;
 using Avalonia.UnitTests;
+using Avalonia.VisualTree;
 using Xunit;
 
 namespace Avalonia.Controls.UnitTests.Primitives
@@ -35,6 +38,25 @@ namespace Avalonia.Controls.UnitTests.Primitives
             }
         }
 
+        [Fact]
+        public void PopupRoot_StylingParent_Is_Popup()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var target = new TemplatedControlWithPopup
+                {
+                    PopupContent = new Canvas(),
+                };
+
+                var root = new TestRoot { Child = target };
+
+                target.ApplyTemplate();
+                target.Popup.Open();
+
+                Assert.Equal(target.Popup, ((IStyleHost)target.Popup.PopupRoot).StylingParent);
+            }
+        }
+
         [Fact]
         public void Attaching_PopupRoot_To_Parent_Logical_Tree_Raises_DetachedFromLogicalTree_And_AttachedToLogicalTree()
         {
@@ -90,14 +112,33 @@ namespace Avalonia.Controls.UnitTests.Primitives
             }
         }
 
+        [Fact]
+        public void Clearing_Content_Of_Popup_In_ControlTemplate_Doesnt_Crash()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var target = new TemplatedControlWithPopup
+                {
+                    PopupContent = new Canvas(),
+                };
+
+                var root = new TestRoot { Child = target };
+
+                target.ApplyTemplate();
+                target.Popup.Open();
+                target.PopupContent = null;
+            }
+        }
+
         private PopupRoot CreateTarget()
         {
             var result = new PopupRoot
             {
-                Template = new FuncControlTemplate<PopupRoot>(_ =>
+                Template = new FuncControlTemplate<PopupRoot>(parent =>
                     new ContentPresenter
                     {
                         Name = "PART_ContentPresenter",
+                        [!ContentPresenter.ContentProperty] = parent[!PopupRoot.ContentProperty],
                     }),
             };
 
@@ -105,5 +146,33 @@ namespace Avalonia.Controls.UnitTests.Primitives
 
             return result;
         }
+
+        private class TemplatedControlWithPopup : TemplatedControl
+        {
+            public static readonly AvaloniaProperty<Control> PopupContentProperty =
+                AvaloniaProperty.Register<TemplatedControlWithPopup, Control>(nameof(PopupContent));
+
+            public TemplatedControlWithPopup()
+            {
+                Template = new FuncControlTemplate<TemplatedControlWithPopup>(parent =>
+                    new Popup
+                    {
+                        [!Popup.ChildProperty] = parent[!TemplatedControlWithPopup.PopupContentProperty],
+                    });
+            }
+
+            public Popup Popup { get; private set; }
+
+            public Control PopupContent
+            {
+                get => GetValue(PopupContentProperty);
+                set => SetValue(PopupContentProperty, value);
+            }
+
+            protected override void OnTemplateApplied(TemplateAppliedEventArgs e)
+            {
+                Popup = (Popup)this.GetVisualChildren().Single();
+            }
+        }
     }
 }
diff --git a/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs b/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
index 85a450e1dc..84ea717bab 100644
--- a/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
@@ -15,6 +15,7 @@ using Avalonia.Styling;
 using Avalonia.UnitTests;
 using Avalonia.VisualTree;
 using Xunit;
+using Avalonia.Input;
 
 namespace Avalonia.Controls.UnitTests.Primitives
 {
@@ -189,12 +190,14 @@ namespace Avalonia.Controls.UnitTests.Primitives
         {
             using (CreateServices())
             {
+                var window = new Window();
                 var target = new Popup();
                 var child = new Control();
 
+                window.Content = target;
                 target.Open();
 
-                Assert.Equal(1, target.PopupRoot.GetVisualChildren().Count());
+                Assert.Single(target.PopupRoot.GetVisualChildren());
 
                 var templatedChild = target.PopupRoot.GetVisualChildren().Single();
                 Assert.IsType<ContentPresenter>(templatedChild);
@@ -214,7 +217,8 @@ namespace Avalonia.Controls.UnitTests.Primitives
                     {
                         Content = new Border(),
                         Template = new FuncControlTemplate<PopupContentControl>(PopupContentControlTemplate),
-                    }
+                    },
+                    StylingParent = AvaloniaLocator.Current.GetService<IGlobalStyles>()
                 };
 
                 target.ApplyTemplate();
@@ -306,7 +310,8 @@ namespace Avalonia.Controls.UnitTests.Primitives
                 .Bind<IGlobalStyles>().ToFunc(() => globalStyles.Object)
                 .Bind<IWindowingPlatform>().ToConstant(new WindowingPlatformMock())
                 .Bind<IStyler>().ToTransient<Styler>()
-                .Bind<IPlatformRenderInterface>().ToFunc(() => renderInterface.Object);
+                .Bind<IPlatformRenderInterface>().ToFunc(() => renderInterface.Object)
+                .Bind<IInputManager>().ToConstant(new InputManager());
             
             return result;
         }
diff --git a/tests/Avalonia.Controls.UnitTests/Primitives/RangeBaseTests.cs b/tests/Avalonia.Controls.UnitTests/Primitives/RangeBaseTests.cs
index d3ed077cbf..2dfb30a9f0 100644
--- a/tests/Avalonia.Controls.UnitTests/Primitives/RangeBaseTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Primitives/RangeBaseTests.cs
@@ -2,7 +2,12 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using System.ComponentModel;
 using Avalonia.Controls.Primitives;
+using Avalonia.Controls.Templates;
+using Avalonia.Data;
+using Avalonia.Markup.Xaml.Data;
+using Avalonia.Styling;
 using Xunit;
 
 namespace Avalonia.Controls.UnitTests.Primitives
@@ -87,8 +92,111 @@ namespace Avalonia.Controls.UnitTests.Primitives
             Assert.Throws<ArgumentException>(() => target.Value = double.NegativeInfinity);
         }
 
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void SetValue_Should_Not_Cause_StackOverflow(bool useXamlBinding)
+        {
+            var viewModel = new TestStackOverflowViewModel()
+            {
+                Value = 50
+            };
+
+            Track track = null;
+
+            var target = new TestRange()
+            {
+                Template = new FuncControlTemplate<RangeBase>(c =>
+                {
+                    track = new Track()
+                    {
+                        Width = 100,
+                        Orientation = Orientation.Horizontal,
+                        [~~Track.MinimumProperty] = c[~~RangeBase.MinimumProperty],
+                        [~~Track.MaximumProperty] = c[~~RangeBase.MaximumProperty],
+
+                        Name = "PART_Track",
+                        Thumb = new Thumb()
+                    };
+
+                    if (useXamlBinding)
+                    {
+                        track.Bind(Track.ValueProperty, new Binding("Value")
+                                                    {
+                                                        Mode = BindingMode.TwoWay,
+                                                        Source = c,
+                                                        Priority = BindingPriority.Style
+                                                    });
+                    }
+                    else
+                    {
+                        track[~~Track.ValueProperty] = c[~~RangeBase.ValueProperty];
+                    }
+
+                    return track;
+                }),
+                Minimum = 0,
+                Maximum = 100,
+                DataContext = viewModel
+            };
+
+            target.Bind(TestRange.ValueProperty, new Binding("Value") { Mode = BindingMode.TwoWay });
+
+            target.ApplyTemplate();
+            track.Measure(new Size(100, 0));
+            track.Arrange(new Rect(0, 0, 100, 0));
+
+            Assert.Equal(1, viewModel.SetterInvokedCount);
+
+            // Issues #855 and #824 were causing a StackOverflowException at this point.
+            target.Value = 51.001;
+
+            Assert.Equal(2, viewModel.SetterInvokedCount);
+
+            double expected = 51;
+
+            Assert.Equal(expected, viewModel.Value);
+            Assert.Equal(expected, target.Value);
+            Assert.Equal(expected, track.Value);
+        }
+
         private class TestRange : RangeBase
         {
         }
+
+        private class TestStackOverflowViewModel : INotifyPropertyChanged
+        {
+            public int SetterInvokedCount { get; private set; }
+
+            public const int MaxInvokedCount = 1000;
+
+            private double _value;
+
+            public event PropertyChangedEventHandler PropertyChanged;
+
+            public double Value
+            {
+                get { return _value; }
+                set
+                {
+                    if (_value != value)
+                    {
+                        SetterInvokedCount++;
+                        if (SetterInvokedCount < MaxInvokedCount)
+                        {
+                            _value = (int)value;
+                            if (_value > 75) _value = 75;
+                            if (_value < 25) _value = 25;
+                        }
+                        else
+                        {
+                            _value = value;
+                        }
+
+                        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
+                    }
+                }
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/tests/Avalonia.Controls.UnitTests/Primitives/ScrollBarTests.cs b/tests/Avalonia.Controls.UnitTests/Primitives/ScrollBarTests.cs
index 5b1ade9c47..0af4d791c7 100644
--- a/tests/Avalonia.Controls.UnitTests/Primitives/ScrollBarTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Primitives/ScrollBarTests.cs
@@ -24,7 +24,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
             var track = (Track)target.GetTemplateChildren().First(x => x.Name == "track");
             target.Value = 50;
 
-            Assert.Equal(track.Value, 50);
+            Assert.Equal(50, track.Value);
         }
 
         [Fact]
@@ -39,7 +39,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
             var track = (Track)target.GetTemplateChildren().First(x => x.Name == "track");
             track.Value = 50;
 
-            Assert.Equal(target.Value, 50);
+            Assert.Equal(50, target.Value);
         }
 
         [Fact]
@@ -56,7 +56,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
             target.Value = 25;
             track.Value = 50;
 
-            Assert.Equal(target.Value, 50);
+            Assert.Equal(50, target.Value);
         }
 
         [Fact]
diff --git a/tests/Avalonia.Controls.UnitTests/Primitives/TemplatedControlTests.cs b/tests/Avalonia.Controls.UnitTests/Primitives/TemplatedControlTests.cs
index be3c34ac2e..cd71717619 100644
--- a/tests/Avalonia.Controls.UnitTests/Primitives/TemplatedControlTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Primitives/TemplatedControlTests.cs
@@ -67,7 +67,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
                 {
                     Child = new Panel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new TextBlock(),
                             new Border(),
@@ -101,7 +101,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
                 {
                     Child = new Panel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new TextBlock(),
                             new Border(),
@@ -124,7 +124,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
                 {
                     Child = new Panel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new TextBlock(),
                             new Border(),
@@ -189,7 +189,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
                         {
                             return new StackPanel
                             {
-                                Children = new Controls
+                                Children =
                                 {
                                     new TextBlock
                                     {
diff --git a/tests/Avalonia.Controls.UnitTests/Primitives/ToggleButtonTests.cs b/tests/Avalonia.Controls.UnitTests/Primitives/ToggleButtonTests.cs
new file mode 100644
index 0000000000..db60d05a34
--- /dev/null
+++ b/tests/Avalonia.Controls.UnitTests/Primitives/ToggleButtonTests.cs
@@ -0,0 +1,57 @@
+using Avalonia.Markup.Xaml.Data;
+using Avalonia.UnitTests;
+
+using Xunit;
+
+namespace Avalonia.Controls.Primitives.UnitTests
+{
+    public class ToggleButtonTests
+    {
+        private const string uncheckedClass = ":unchecked";
+        private const string checkedClass = ":checked";
+        private const string indeterminateClass = ":indeterminate";
+
+        [Theory]
+        [InlineData(false, uncheckedClass, false)]
+        [InlineData(false, uncheckedClass, true)]
+        [InlineData(true, checkedClass, false)]
+        [InlineData(true, checkedClass, true)]
+        [InlineData(null, indeterminateClass, false)]
+        [InlineData(null, indeterminateClass, true)]
+        public void ToggleButton_Has_Correct_Class_According_To_Is_Checked(bool? isChecked, string expectedClass, bool isThreeState)
+        {
+            var toggleButton = new ToggleButton();
+            toggleButton.IsThreeState = isThreeState;
+            toggleButton.IsChecked = isChecked;
+
+            Assert.Contains(expectedClass, toggleButton.Classes);
+        }
+
+        [Fact]
+        public void ToggleButton_Is_Checked_Binds_To_Bool()
+        {
+            var toggleButton = new ToggleButton();
+            var source = new Class1();
+
+            toggleButton.DataContext = source;
+            toggleButton.Bind(ToggleButton.IsCheckedProperty, new Binding("Foo"));
+
+            source.Foo = true;
+            Assert.True(toggleButton.IsChecked);
+
+            source.Foo = false;
+            Assert.False(toggleButton.IsChecked);
+        }
+
+        private class Class1 : NotifyingBase
+        {
+            private bool _foo;
+
+            public bool Foo
+            {
+                get { return _foo; }
+                set { _foo = value; RaisePropertyChanged(); }
+            }
+        }
+    }
+}
diff --git a/tests/Avalonia.Controls.UnitTests/Primitives/TrackTests.cs b/tests/Avalonia.Controls.UnitTests/Primitives/TrackTests.cs
index f07a5f5095..5396a43f3a 100644
--- a/tests/Avalonia.Controls.UnitTests/Primitives/TrackTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Primitives/TrackTests.cs
@@ -140,5 +140,31 @@ namespace Avalonia.Controls.UnitTests.Primitives
             Assert.Same(thumb.Parent, target);
             Assert.Equal(new[] { thumb }, ((ILogical)target).LogicalChildren);
         }
+
+        [Fact]
+        public void Should_Not_Pass_Invalid_Arrange_Rect()
+        {
+            var thumb = new Thumb { Width = 100.873106060606 };
+            var increaseButton = new Button { Width = 10 };
+            var decreaseButton = new Button { Width = 10 };
+
+            var target = new Track
+            {
+                Height = 12,
+                Thumb = thumb,
+                IncreaseButton = increaseButton,
+                DecreaseButton = decreaseButton,
+                Orientation = Orientation.Horizontal,
+                Minimum = 0,
+                Maximum = 287,
+                Value = 287,
+                ViewportSize = 241,
+            };
+
+            target.Measure(Size.Infinity);
+
+            // #1297 was occuring here.
+            target.Arrange(new Rect(0, 0, 221, 12));
+        }
     }
 }
diff --git a/tests/Avalonia.Controls.UnitTests/RadioButtonTests.cs b/tests/Avalonia.Controls.UnitTests/RadioButtonTests.cs
new file mode 100644
index 0000000000..37fb52beeb
--- /dev/null
+++ b/tests/Avalonia.Controls.UnitTests/RadioButtonTests.cs
@@ -0,0 +1,36 @@
+using Avalonia.Markup.Xaml.Data;
+using Avalonia.UnitTests;
+
+using Xunit;
+
+namespace Avalonia.Controls.UnitTests
+{
+    public class RadioButtonTests
+    {
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void Indeterminate_RadioButton_Is_Not_Unchecked_After_Checking_Other_Radio_Button(bool isThreeState)
+        {
+            var panel = new Panel();
+
+            var radioButton1 = new RadioButton();
+            radioButton1.IsThreeState = false;
+            radioButton1.IsChecked = false;
+
+            var radioButton2 = new RadioButton();
+            radioButton2.IsThreeState = isThreeState;
+            radioButton2.IsChecked = null;
+
+            panel.Children.Add(radioButton1);
+            panel.Children.Add(radioButton2);
+
+            Assert.Null(radioButton2.IsChecked);
+
+            radioButton1.IsChecked = true;
+
+            Assert.True(radioButton1.IsChecked);
+            Assert.Null(radioButton2.IsChecked);
+        }
+    }
+}
diff --git a/tests/Avalonia.Controls.UnitTests/ScrollViewerTests.cs b/tests/Avalonia.Controls.UnitTests/ScrollViewerTests.cs
index 8f815a85c9..68dcfcb770 100644
--- a/tests/Avalonia.Controls.UnitTests/ScrollViewerTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ScrollViewerTests.cs
@@ -50,7 +50,7 @@ namespace Avalonia.Controls.UnitTests
                     new RowDefinition(1, GridUnitType.Star),
                     new RowDefinition(GridLength.Auto),
                 },
-                Children = new Controls
+                Children =
                 {
                     new ScrollContentPresenter
                     {
diff --git a/tests/Avalonia.Controls.UnitTests/StackPanelTests.cs b/tests/Avalonia.Controls.UnitTests/StackPanelTests.cs
index 56412d732b..ba80cb779a 100644
--- a/tests/Avalonia.Controls.UnitTests/StackPanelTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/StackPanelTests.cs
@@ -13,7 +13,7 @@ namespace Avalonia.Controls.UnitTests
         {
             var target = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new Border { Height = 20, Width = 120 },
                     new Border { Height = 30 },
@@ -36,7 +36,7 @@ namespace Avalonia.Controls.UnitTests
             var target = new StackPanel
             {
                 Orientation = Orientation.Horizontal,
-                Children = new Controls
+                Children =
                 {
                     new Border { Width = 20, Height = 120 },
                     new Border { Width = 30 },
@@ -59,7 +59,7 @@ namespace Avalonia.Controls.UnitTests
             var target = new StackPanel
             {
                 Gap = 10,
-                Children = new Controls
+                Children =
                 {
                     new Border { Height = 20, Width = 120 },
                     new Border { Height = 30 },
@@ -83,7 +83,7 @@ namespace Avalonia.Controls.UnitTests
             {
                 Gap = 10,
                 Orientation = Orientation.Horizontal,
-                Children = new Controls
+                Children =
                 {
                     new Border { Width = 20, Height = 120 },
                     new Border { Width = 30 },
@@ -106,7 +106,7 @@ namespace Avalonia.Controls.UnitTests
             var target = new StackPanel
             {
                 Height = 60,
-                Children = new Controls
+                Children =
                 {
                     new Border { Height = 20, Width = 120 },
                     new Border { Height = 30 },
@@ -130,7 +130,7 @@ namespace Avalonia.Controls.UnitTests
             {
                 Width = 60,
                 Orientation = Orientation.Horizontal,
-                Children = new Controls
+                Children =
                 {
                     new Border { Width = 20, Height = 120 },
                     new Border { Width = 30 },
diff --git a/tests/Avalonia.Controls.UnitTests/TabControlTests.cs b/tests/Avalonia.Controls.UnitTests/TabControlTests.cs
index 638d773cd0..67b224d6a0 100644
--- a/tests/Avalonia.Controls.UnitTests/TabControlTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/TabControlTests.cs
@@ -272,7 +272,7 @@ namespace Avalonia.Controls.UnitTests
         {
             return new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new TabStrip
                     {
diff --git a/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs b/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs
index 26fc2a2461..b091f6826e 100644
--- a/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/TextBoxTests.cs
@@ -202,6 +202,22 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Fact]
+        public void Setting_SelectionStart_To_SelectionEnd_Sets_CaretPosition_To_SelectionStart()
+        {
+            using (UnitTestApplication.Start(Services))
+            {
+                var textBox = new TextBox
+                {
+                    Text = "0123456789"
+                };
+
+                textBox.SelectionStart = 2;
+                textBox.SelectionEnd = 2;
+                Assert.Equal(2, textBox.CaretIndex);
+            }
+        }
+
         [Fact]
         public void Setting_Text_Updates_CaretPosition()
         {
diff --git a/tests/Avalonia.Controls.UnitTests/TextBoxTests_DataValidation.cs b/tests/Avalonia.Controls.UnitTests/TextBoxTests_DataValidation.cs
index ff3634b9fe..daf2715d84 100644
--- a/tests/Avalonia.Controls.UnitTests/TextBoxTests_DataValidation.cs
+++ b/tests/Avalonia.Controls.UnitTests/TextBoxTests_DataValidation.cs
@@ -33,11 +33,11 @@ namespace Avalonia.Controls.UnitTests
 
                 target.ApplyTemplate();
 
-                Assert.False(target.Classes.Contains(":error"));
+                Assert.DoesNotContain(":error", target.Classes);
                 target.Text = "20";
-                Assert.True(target.Classes.Contains(":error"));
+                Assert.Contains(":error", target.Classes);
                 target.Text = "1";
-                Assert.False(target.Classes.Contains(":error"));
+                Assert.DoesNotContain(":error", target.Classes);
             }
         }
 
@@ -57,7 +57,7 @@ namespace Avalonia.Controls.UnitTests
 
                 Assert.Null(target.DataValidationErrors);
                 target.Text = "20";
-                Assert.Equal(1, target.DataValidationErrors.Count());
+                Assert.Single(target.DataValidationErrors);
                 Assert.IsType<InvalidOperationException>(target.DataValidationErrors.Single());
                 target.Text = "1";
                 Assert.Null(target.DataValidationErrors);
diff --git a/tests/Avalonia.Controls.UnitTests/TreeViewTests.cs b/tests/Avalonia.Controls.UnitTests/TreeViewTests.cs
index 17eccc96bc..625d9eb26e 100644
--- a/tests/Avalonia.Controls.UnitTests/TreeViewTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/TreeViewTests.cs
@@ -432,7 +432,7 @@ namespace Avalonia.Controls.UnitTests
         {
             return new FuncControlTemplate<TreeViewItem>(parent => new Panel
             {
-                Children = new Controls
+                Children =
                 {
                     new ContentPresenter
                     {
diff --git a/tests/Avalonia.Controls.UnitTests/WrapPanelTests.cs b/tests/Avalonia.Controls.UnitTests/WrapPanelTests.cs
index 1a46e24b16..cd35627064 100644
--- a/tests/Avalonia.Controls.UnitTests/WrapPanelTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/WrapPanelTests.cs
@@ -12,12 +12,12 @@ namespace Avalonia.Controls.UnitTests
         {
             var target = new WrapPanel()
                          {
-                             Width = 100,
-                             Children = new Controls
-                                        {
-                                            new Border { Height = 50, Width = 100 },
-                                            new Border { Height = 50, Width = 100 },
-                                        }
+                            Width = 100,
+                            Children =
+                            {
+                                new Border { Height = 50, Width = 100 },
+                                new Border { Height = 50, Width = 100 },
+                            }
                          };
 
             target.Measure(Size.Infinity);
@@ -33,12 +33,12 @@ namespace Avalonia.Controls.UnitTests
         {
             var target = new WrapPanel()
                          {
-                             Width = 200,
-                             Children = new Controls
-                                        {
-                                            new Border { Height = 50, Width = 100 },
-                                            new Border { Height = 50, Width = 100 },
-                                        }
+                            Width = 200,
+                            Children =
+                            {
+                                new Border { Height = 50, Width = 100 },
+                                new Border { Height = 50, Width = 100 },
+                            }
                          };
 
             target.Measure(Size.Infinity);
@@ -54,13 +54,13 @@ namespace Avalonia.Controls.UnitTests
         {
             var target = new WrapPanel()
                          {
-                             Orientation = Orientation.Vertical,
-                             Height = 120,
-                             Children = new Controls
-                                        {
-                                            new Border { Height = 50, Width = 100 },
-                                            new Border { Height = 50, Width = 100 },
-                                        }
+                            Orientation = Orientation.Vertical,
+                            Height = 120,
+                            Children =
+                            {
+                                new Border { Height = 50, Width = 100 },
+                                new Border { Height = 50, Width = 100 },
+                            }
                          };
 
             target.Measure(Size.Infinity);
@@ -76,13 +76,13 @@ namespace Avalonia.Controls.UnitTests
         {
             var target = new WrapPanel()
                          {
-                             Orientation = Orientation.Vertical,
-                             Height = 60,
-                             Children = new Controls
-                                        {
-                                            new Border { Height = 50, Width = 100 },
-                                            new Border { Height = 50, Width = 100 },
-                                        }
+                            Orientation = Orientation.Vertical,
+                            Height = 60,
+                            Children =
+                            {
+                                new Border { Height = 50, Width = 100 },
+                                new Border { Height = 50, Width = 100 },
+                            }
                          };
 
             target.Measure(Size.Infinity);
diff --git a/tests/Avalonia.Input.UnitTests/KeyGestureParseTests.cs b/tests/Avalonia.Input.UnitTests/KeyGestureParseTests.cs
deleted file mode 100644
index d26b03ad80..0000000000
--- a/tests/Avalonia.Input.UnitTests/KeyGestureParseTests.cs
+++ /dev/null
@@ -1,28 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using Xunit;
-
-namespace Avalonia.Input.UnitTests
-{
-    public class KeyGestureParseTests
-    {
-        private static readonly Dictionary<string, KeyGesture> SampleData = new Dictionary<string, KeyGesture>
-        {
-            {"Ctrl+A", new KeyGesture {Key = Key.A, Modifiers = InputModifiers.Control}},
-            {"  \tShift\t+Alt +B", new KeyGesture {Key = Key.B, Modifiers = InputModifiers.Shift|InputModifiers.Alt} },
-            {"Control++", new KeyGesture {Key = Key.OemPlus, Modifiers = InputModifiers.Control} }
-        };
-            
-            
-            
-        [Fact]
-        public void Key_Gesture_Is_Able_To_Parse_Sample_Data()
-        {
-            foreach (var d in SampleData)
-                Assert.Equal(d.Value, KeyGesture.Parse(d.Key));
-        }
-    }
-}
diff --git a/tests/Avalonia.Input.UnitTests/KeyGestureTests.cs b/tests/Avalonia.Input.UnitTests/KeyGestureTests.cs
new file mode 100644
index 0000000000..006ed1140e
--- /dev/null
+++ b/tests/Avalonia.Input.UnitTests/KeyGestureTests.cs
@@ -0,0 +1,44 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace Avalonia.Input.UnitTests
+{
+    public class KeyGestureTests
+    {
+        public static readonly IEnumerable<object[]> SampleData = new object[][]
+        {
+            new object[]{"Ctrl+A", new KeyGesture {Key = Key.A, Modifiers = InputModifiers.Control}},
+            new object[]{"  \tShift\t+Alt +B", new KeyGesture {Key = Key.B, Modifiers = InputModifiers.Shift|InputModifiers.Alt} },
+            new object[]{"Control++", new KeyGesture {Key = Key.OemPlus, Modifiers = InputModifiers.Control} }
+        };
+            
+            
+            
+        [Theory]
+        [MemberData(nameof(SampleData))]
+        public void Key_Gesture_Is_Able_To_Parse_Sample_Data(string text, KeyGesture gesture)
+        {
+            Assert.Equal(gesture, KeyGesture.Parse(text));
+        }
+
+        [Theory]
+        [InlineData(Key.OemMinus, Key.Subtract)]
+        [InlineData(Key.OemPlus, Key.Add)]
+        [InlineData(Key.OemPeriod, Key.Decimal)]
+        public void Key_Gesture_Matches_NumPad_To_Regular_Digit(Key gestureKey, Key pressedKey)
+        {
+            var keyGesture = new KeyGesture
+            {
+                Key = gestureKey
+            };
+            Assert.True(keyGesture.Matches(new KeyEventArgs
+            {
+                Key = pressedKey
+            }));
+        }
+    }
+}
diff --git a/tests/Avalonia.Input.UnitTests/KeyboardNavigationTests_Arrows.cs b/tests/Avalonia.Input.UnitTests/KeyboardNavigationTests_Arrows.cs
index 2b9b0baf01..b81b724e2a 100644
--- a/tests/Avalonia.Input.UnitTests/KeyboardNavigationTests_Arrows.cs
+++ b/tests/Avalonia.Input.UnitTests/KeyboardNavigationTests_Arrows.cs
@@ -6,8 +6,6 @@ using Xunit;
 
 namespace Avalonia.Input.UnitTests
 {
-    using Controls = Controls.Controls;
-
     public class KeyboardNavigationTests_Arrows
     {
         [Fact]
@@ -18,12 +16,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (current = new Button { Name = "Button2" }),
@@ -33,7 +31,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -56,12 +54,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -71,7 +69,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -94,12 +92,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -123,16 +121,16 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new StackPanel
                             {
                                 [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                                Children = new Controls
+                                Children =
                                 {
                                     new Button { Name = "Button1" },
                                     new Button { Name = "Button2" },
@@ -144,7 +142,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -167,7 +165,7 @@ namespace Avalonia.Input.UnitTests
             var top = new StackPanel
             {
                 [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                Children = new Controls
+                Children =
                 {
                     (next = new Button { Name = "Button1" }),
                 }
@@ -187,17 +185,17 @@ namespace Avalonia.Input.UnitTests
             var top = new StackPanel
             {
                 [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             new StackPanel
                             {
                                 [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                                Children = new Controls
+                                Children =
                                 {
                                     (next = new Button { Name = "Button1" }),
                                     new Button { Name = "Button2" },
@@ -209,7 +207,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -232,12 +230,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Cycle,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (current = new Button { Name = "Button2" }),
@@ -246,7 +244,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -269,12 +267,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Cycle,
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button1" }),
                             new Button { Name = "Button2" },
@@ -283,7 +281,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -306,12 +304,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (current = new Button { Name = "Button2" }),
@@ -321,7 +319,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -343,12 +341,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -358,7 +356,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -380,12 +378,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.None,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (current = new Button { Name = "Button2" }),
@@ -395,7 +393,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -418,12 +416,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (next = new Button { Name = "Button2" }),
@@ -433,7 +431,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -456,12 +454,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -471,7 +469,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             (current = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -495,12 +493,12 @@ namespace Avalonia.Input.UnitTests
             var top = new StackPanel
             {
                 [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -524,16 +522,16 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new StackPanel
                             {
                                 [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                                Children = new Controls
+                                Children =
                                 {
                                     new Button { Name = "Button1" },
                                     new Button { Name = "Button2" },
@@ -545,7 +543,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             (current = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -568,16 +566,16 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new StackPanel
                             {
                                 [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                                Children = new Controls
+                                Children =
                                 {
                                     (current = new Button { Name = "Button1" }),
                                     new Button { Name = "Button2" },
@@ -589,7 +587,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Continue,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -632,12 +630,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Cycle,
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button1" }),
                             (current = new Button { Name = "Button2" }),
@@ -647,7 +645,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Cycle,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -670,12 +668,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Cycle,
-                        Children = new Controls
+                        Children =
                         {
                             (current = new Button { Name = "Button1" }),
                             new Button { Name = "Button2" },
@@ -685,7 +683,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Cycle,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -708,12 +706,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button1" }),
                             (current = new Button { Name = "Button2" }),
@@ -723,7 +721,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -745,12 +743,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             (current = new Button { Name = "Button1" }),
                             new Button { Name = "Button2" },
@@ -760,7 +758,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -783,7 +781,7 @@ namespace Avalonia.Input.UnitTests
             var top = new StackPanel
             {
                 [KeyboardNavigation.DirectionalNavigationProperty] = KeyboardNavigationMode.Contained,
-                Children = new Controls
+                Children =
                 {
                     (current = new Decorator
                     {
diff --git a/tests/Avalonia.Input.UnitTests/KeyboardNavigationTests_Tab.cs b/tests/Avalonia.Input.UnitTests/KeyboardNavigationTests_Tab.cs
index 2cc7a4281b..ad70dcd470 100644
--- a/tests/Avalonia.Input.UnitTests/KeyboardNavigationTests_Tab.cs
+++ b/tests/Avalonia.Input.UnitTests/KeyboardNavigationTests_Tab.cs
@@ -6,8 +6,6 @@ using Xunit;
 
 namespace Avalonia.Input.UnitTests
 {
-    using Controls = Controls.Controls;
-
     public class KeyboardNavigationTests_Tab
     {
         [Fact]
@@ -18,11 +16,11 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (current = new Button { Name = "Button2" }),
@@ -31,7 +29,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -54,11 +52,11 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -67,7 +65,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -90,11 +88,11 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button1" }),
                             new Button { Name = "Button2" },
@@ -104,11 +102,11 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.None,
-                        Children = new Controls
+                        Children =
                         {
                             new StackPanel
                             {
-                                Children = new Controls
+                                Children =
                                 {
                                     new Button { Name = "Button4" },
                                     new Button { Name = "Button5" },
@@ -133,11 +131,11 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -161,15 +159,15 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new StackPanel
                             {
-                                Children = new Controls
+                                Children =
                                 {
                                     new Button { Name = "Button1" },
                                     new Button { Name = "Button2" },
@@ -180,7 +178,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -202,7 +200,7 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     (next = new Button { Name = "Button1" }),
                 }
@@ -221,15 +219,15 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new StackPanel
                             {
-                                Children = new Controls
+                                Children =
                                 {
                                     (next = new Button { Name = "Button1" }),
                                     new Button { Name = "Button2" },
@@ -240,7 +238,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -263,12 +261,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Cycle,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (current = new Button { Name = "Button2" }),
@@ -277,7 +275,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -300,12 +298,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Cycle,
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button1" }),
                             new Button { Name = "Button2" },
@@ -314,7 +312,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -337,12 +335,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (current = new Button { Name = "Button2" }),
@@ -351,7 +349,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -373,12 +371,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -387,7 +385,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -410,12 +408,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Once,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (current = new Button { Name = "Button2" }),
@@ -424,7 +422,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -448,12 +446,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     (container = new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Once,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (next = new Button { Name = "Button2" }),
@@ -462,7 +460,7 @@ namespace Avalonia.Input.UnitTests
                     }),
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -487,12 +485,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.None,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (current = new Button { Name = "Button2" }),
@@ -501,7 +499,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -525,12 +523,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     (container = new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.None,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -539,7 +537,7 @@ namespace Avalonia.Input.UnitTests
                     }),
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -564,11 +562,11 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (next = new Button { Name = "Button2" }),
@@ -577,7 +575,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -600,11 +598,11 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -613,7 +611,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             (current = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -636,11 +634,11 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -664,15 +662,15 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new StackPanel
                             {
-                                Children = new Controls
+                                Children =
                                 {
                                     new Button { Name = "Button1" },
                                     new Button { Name = "Button2" },
@@ -683,7 +681,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             (current = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -706,15 +704,15 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new StackPanel
                             {
-                                Children = new Controls
+                                Children =
                                 {
                                     (current = new Button { Name = "Button1" }),
                                     new Button { Name = "Button2" },
@@ -725,7 +723,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -767,12 +765,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Cycle,
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button1" }),
                             (current = new Button { Name = "Button2" }),
@@ -781,7 +779,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -804,12 +802,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Cycle,
-                        Children = new Controls
+                        Children =
                         {
                             (current = new Button { Name = "Button1" }),
                             new Button { Name = "Button2" },
@@ -818,7 +816,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -841,12 +839,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button1" }),
                             (current = new Button { Name = "Button2" }),
@@ -855,7 +853,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -877,12 +875,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Contained,
-                        Children = new Controls
+                        Children =
                         {
                             (current = new Button { Name = "Button1" }),
                             new Button { Name = "Button2" },
@@ -891,7 +889,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             new Button { Name = "Button5" },
@@ -914,11 +912,11 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             new Button { Name = "Button2" },
@@ -928,7 +926,7 @@ namespace Avalonia.Input.UnitTests
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Once,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button4" },
                             (current = new Button { Name = "Button5" }),
@@ -952,12 +950,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     (container = new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Once,
-                        Children = new Controls
+                        Children =
                         {
                             new Button { Name = "Button1" },
                             (next = new Button { Name = "Button2" }),
@@ -966,7 +964,7 @@ namespace Avalonia.Input.UnitTests
                     }),
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             (current = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -991,12 +989,12 @@ namespace Avalonia.Input.UnitTests
 
             var top = new StackPanel
             {
-                Children = new Controls
+                Children =
                 {
                     new StackPanel
                     {
                         [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Once,
-                        Children = new Controls
+                        Children =
                         {
                             (next = new Button { Name = "Button1" }),
                             new Button { Name = "Button2" },
@@ -1005,7 +1003,7 @@ namespace Avalonia.Input.UnitTests
                     },
                     new StackPanel
                     {
-                        Children = new Controls
+                        Children =
                         {
                             (current = new Button { Name = "Button4" }),
                             new Button { Name = "Button5" },
@@ -1028,7 +1026,7 @@ namespace Avalonia.Input.UnitTests
             var top = new StackPanel
             {
                 [KeyboardNavigation.TabNavigationProperty] = KeyboardNavigationMode.Contained,
-                Children = new Controls
+                Children =
                 {
                     (current = new Decorator
                     {
diff --git a/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs b/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
index 00d4af7e4d..1a07bdc7d1 100644
--- a/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
+++ b/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
@@ -109,7 +109,7 @@ namespace Avalonia.Layout.UnitTests
                 var presenters = scrollViewer.GetTemplateChildren().OfType<ScrollContentPresenter>().ToList();
 
                 Assert.Equal(2, scrollBars.Count);
-                Assert.Equal(1, presenters.Count);
+                Assert.Single(presenters);
 
                 var presenter = presenters[0];
                 Assert.Equal(new Size(190, 190), presenter.Bounds.Size);
diff --git a/tests/Avalonia.Layout.UnitTests/LayoutManagerTests.cs b/tests/Avalonia.Layout.UnitTests/LayoutManagerTests.cs
index 361e7678be..4fce3fec0e 100644
--- a/tests/Avalonia.Layout.UnitTests/LayoutManagerTests.cs
+++ b/tests/Avalonia.Layout.UnitTests/LayoutManagerTests.cs
@@ -275,10 +275,10 @@ namespace Avalonia.Layout.UnitTests
                 {
                     Child = panel = new StackPanel
                     {
-                        Children = new Controls.Controls
-                    {
-                        (border = new Border())
-                    }
+                        Children =
+                        {
+                            (border = new Border())
+                        }
                     }
                 };
 
diff --git a/tests/Avalonia.LeakTests/ControlTests.cs b/tests/Avalonia.LeakTests/ControlTests.cs
index 979127cd14..fe3ad59bb4 100644
--- a/tests/Avalonia.LeakTests/ControlTests.cs
+++ b/tests/Avalonia.LeakTests/ControlTests.cs
@@ -155,7 +155,7 @@ namespace Avalonia.LeakTests
                     // template applied.
                     LayoutManager.Instance.ExecuteInitialLayoutPass(window);
                     Assert.IsType<TextBox>(window.Presenter.Child);
-                    Assert.NotEqual(0, window.Presenter.Child.GetVisualChildren().Count());
+                    Assert.NotEmpty(window.Presenter.Child.GetVisualChildren());
 
                     // Clear the content and ensure the TextBox is removed.
                     window.Content = null;
@@ -290,7 +290,7 @@ namespace Avalonia.LeakTests
 
                     // Do a layout and make sure that TreeViewItems get realized.
                     LayoutManager.Instance.ExecuteInitialLayoutPass(window);
-                    Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
+                    Assert.Single(target.ItemContainerGenerator.Containers);
 
                     // Clear the content and ensure the TreeView is removed.
                     window.Content = null;
diff --git a/tests/Avalonia.Markup.UnitTests/ControlLocatorTests.cs b/tests/Avalonia.Markup.UnitTests/ControlLocatorTests.cs
index a5414f1e8c..b3e983036d 100644
--- a/tests/Avalonia.Markup.UnitTests/ControlLocatorTests.cs
+++ b/tests/Avalonia.Markup.UnitTests/ControlLocatorTests.cs
@@ -23,7 +23,7 @@ namespace Avalonia.Markup.UnitTests
             {
                 Child = new StackPanel
                 {
-                    Children = new Controls.Controls
+                    Children =
                     {
                         (target = new TextBlock { Name = "target" }),
                         (relativeTo = new TextBlock { Name = "start" }),
@@ -49,7 +49,7 @@ namespace Avalonia.Markup.UnitTests
             {
                 Child = (panel = new StackPanel
                 {
-                    Children = new Controls.Controls
+                    Children =
                     {
                         (relativeTo = new TextBlock
                         {
@@ -84,7 +84,7 @@ namespace Avalonia.Markup.UnitTests
             {
                 Child = panel = new StackPanel
                 {
-                    Children = new Controls.Controls
+                    Children =
                     {
                         (target = new TextBlock { Name = "target" }),
                         (relativeTo = new TextBlock { Name = "start" }),
@@ -114,7 +114,7 @@ namespace Avalonia.Markup.UnitTests
             {
                 Child = new StackPanel
                 {
-                    Children = new Controls.Controls
+                    Children =
                     {
                         (relativeTo = new TextBlock
                         {
@@ -129,7 +129,7 @@ namespace Avalonia.Markup.UnitTests
             {
                 Child = new StackPanel
                 {
-                    Children = new Controls.Controls
+                    Children =
                     {
                         (target2 = new TextBlock { Name = "target" }),
                     }
diff --git a/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_DataValidation.cs b/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_DataValidation.cs
index 125bd84f3d..9bf1e4711b 100644
--- a/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_DataValidation.cs
+++ b/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_DataValidation.cs
@@ -78,6 +78,10 @@ namespace Avalonia.Markup.UnitTests.Data
             var data = new IndeiTest();
             var observer = new ExpressionObserver(data, nameof(data.MustBePositive), true);
             var result = new List<object>();
+            
+            var errmsg = string.Empty;
+            try { typeof(IndeiTest).GetProperty(nameof(IndeiTest.MustBePositive)).SetValue(data, "foo"); }
+            catch(Exception e) { errmsg = e.Message; }
 
             observer.Subscribe(x => result.Add(x));
             observer.SetValue(5);
@@ -99,7 +103,7 @@ namespace Avalonia.Markup.UnitTests.Data
 
                 // Exception is thrown by trying to set value to "foo".
                 new BindingNotification(
-                    new ArgumentException("Object of type 'System.String' cannot be converted to type 'System.Int32'."),
+                    new ArgumentException(errmsg),
                     BindingErrorType.DataValidationError),
 
                 // Value is set then validation is updated.
diff --git a/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Negation.cs b/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Negation.cs
index 6a23a24051..f4aa85c393 100644
--- a/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Negation.cs
+++ b/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Negation.cs
@@ -19,7 +19,7 @@ namespace Avalonia.Markup.UnitTests.Data
             var target = new ExpressionObserver(data, "!Foo");
             var result = await target.Take(1);
 
-            Assert.Equal(false, result);
+            Assert.False((bool)result);
 
             GC.KeepAlive(data);
         }
@@ -31,7 +31,7 @@ namespace Avalonia.Markup.UnitTests.Data
             var target = new ExpressionObserver(data, "!Foo");
             var result = await target.Take(1);
 
-            Assert.Equal(true, result);
+            Assert.True((bool)result);
 
             GC.KeepAlive(data);
         }
@@ -43,7 +43,7 @@ namespace Avalonia.Markup.UnitTests.Data
             var target = new ExpressionObserver(data, "!Foo");
             var result = await target.Take(1);
 
-            Assert.Equal(false, result);
+            Assert.False((bool)result);
 
             GC.KeepAlive(data);
         }
@@ -55,7 +55,7 @@ namespace Avalonia.Markup.UnitTests.Data
             var target = new ExpressionObserver(data, "!Foo");
             var result = await target.Take(1);
 
-            Assert.Equal(true, result);
+            Assert.True((bool)result);
 
             GC.KeepAlive(data);
         }
@@ -67,7 +67,7 @@ namespace Avalonia.Markup.UnitTests.Data
             var target = new ExpressionObserver(data, "!Foo");
             var result = await target.Take(1);
 
-            Assert.Equal(false, result);
+            Assert.False((bool)result);
 
             GC.KeepAlive(data);
         }
diff --git a/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Task.cs b/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Task.cs
index c251f4398a..87a8be045b 100644
--- a/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Task.cs
+++ b/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Task.cs
@@ -28,7 +28,7 @@ namespace Avalonia.Markup.UnitTests.Data
                 tcs.SetResult("foo");
                 sync.ExecutePostedCallbacks();
 
-                Assert.Equal(1, result.Count);
+                Assert.Single(result);
                 Assert.IsType<Task<string>>(result[0]);
 
                 GC.KeepAlive(data);
diff --git a/tests/Avalonia.Markup.Xaml.UnitTests/Avalonia.Markup.Xaml.UnitTests.csproj b/tests/Avalonia.Markup.Xaml.UnitTests/Avalonia.Markup.Xaml.UnitTests.csproj
index eb6dc8b5e5..a3e4ad1418 100644
--- a/tests/Avalonia.Markup.Xaml.UnitTests/Avalonia.Markup.Xaml.UnitTests.csproj
+++ b/tests/Avalonia.Markup.Xaml.UnitTests/Avalonia.Markup.Xaml.UnitTests.csproj
@@ -21,6 +21,7 @@
     <ProjectReference Include="..\..\src\Avalonia.Visuals\Avalonia.Visuals.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Styling\Avalonia.Styling.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
+    <ProjectReference Include="..\Avalonia.Base.UnitTests\Avalonia.Base.UnitTests.csproj" />
     <ProjectReference Include="..\Avalonia.UnitTests\Avalonia.UnitTests.csproj" />
   </ItemGroup>
   <ItemGroup>
diff --git a/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests.cs b/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests.cs
index 230e61f300..71c5385c23 100644
--- a/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests.cs
+++ b/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests.cs
@@ -13,6 +13,7 @@ using Moq;
 using Xunit;
 using System.ComponentModel;
 using System.Runtime.CompilerServices;
+using Avalonia.UnitTests;
 
 namespace Avalonia.Markup.Xaml.UnitTests.Data
 {
@@ -337,6 +338,167 @@ namespace Avalonia.Markup.Xaml.UnitTests.Data
             Assert.Equal("foo", target.Content);
         }
 
+        [Fact]
+        public void StyledProperty_SetValue_Should_Not_Cause_StackOverflow_And_Have_Correct_Values()
+        {
+            var viewModel = new TestStackOverflowViewModel()
+            {
+                Value = 50
+            };
+
+            var target = new StyledPropertyClass();
+
+            target.Bind(StyledPropertyClass.DoubleValueProperty,
+                new Binding("Value") { Mode = BindingMode.TwoWay, Source = viewModel });
+
+            var child = new StyledPropertyClass();
+
+            child.Bind(StyledPropertyClass.DoubleValueProperty,
+                new Binding("DoubleValue")
+                {
+                    Mode = BindingMode.TwoWay,
+                    Source = target
+                });
+
+            Assert.Equal(1, viewModel.SetterInvokedCount);
+
+            //here in real life stack overflow exception is thrown issue #855 and #824
+            target.DoubleValue = 51.001;
+
+            Assert.Equal(2, viewModel.SetterInvokedCount);
+
+            double expected = 51;
+
+            Assert.Equal(expected, viewModel.Value);
+            Assert.Equal(expected, target.DoubleValue);
+            Assert.Equal(expected, child.DoubleValue);
+        }
+
+        [Fact]
+        public void SetValue_Should_Not_Cause_StackOverflow_And_Have_Correct_Values()
+        {
+            var viewModel = new TestStackOverflowViewModel()
+            {
+                Value = 50
+            };
+
+            var target = new DirectPropertyClass();
+
+            target.Bind(DirectPropertyClass.DoubleValueProperty, new Binding("Value")
+            {
+                Mode = BindingMode.TwoWay,
+                Source = viewModel
+            });
+
+            var child = new DirectPropertyClass();
+
+            child.Bind(DirectPropertyClass.DoubleValueProperty,
+                new Binding("DoubleValue")
+                {
+                    Mode = BindingMode.TwoWay,
+                    Source = target
+                });
+
+            Assert.Equal(1, viewModel.SetterInvokedCount);
+
+            //here in real life stack overflow exception is thrown issue #855 and #824
+            target.DoubleValue = 51.001;
+
+            Assert.Equal(2, viewModel.SetterInvokedCount);
+
+            double expected = 51;
+
+            Assert.Equal(expected, viewModel.Value);
+            Assert.Equal(expected, target.DoubleValue);
+            Assert.Equal(expected, child.DoubleValue);
+        }
+
+        private class StyledPropertyClass : AvaloniaObject
+        {
+            public static readonly StyledProperty<double> DoubleValueProperty =
+                        AvaloniaProperty.Register<StyledPropertyClass, double>(nameof(DoubleValue));
+
+            public double DoubleValue
+            {
+                get { return GetValue(DoubleValueProperty); }
+                set { SetValue(DoubleValueProperty, value); }
+            }
+        }
+
+        private class DirectPropertyClass : AvaloniaObject
+        {
+            public static readonly DirectProperty<DirectPropertyClass, double> DoubleValueProperty =
+                AvaloniaProperty.RegisterDirect<DirectPropertyClass, double>(
+                    nameof(DoubleValue),
+                    o => o.DoubleValue,
+                    (o, v) => o.DoubleValue = v);
+
+            private double _doubleValue;
+            public double DoubleValue
+            {
+                get { return _doubleValue; }
+                set { SetAndRaise(DoubleValueProperty, ref _doubleValue, value); }
+            }
+        }
+
+        private class TestStackOverflowViewModel : INotifyPropertyChanged
+        {
+            public int SetterInvokedCount { get; private set; }
+
+            public const int MaxInvokedCount = 1000;
+
+            private double _value;
+
+            public event PropertyChangedEventHandler PropertyChanged;
+
+            public double Value
+            {
+                get { return _value; }
+                set
+                {
+                    if (_value != value)
+                    {
+                        SetterInvokedCount++;
+                        if (SetterInvokedCount < MaxInvokedCount)
+                        {
+                            _value = (int)value;
+                            if (_value > 75) _value = 75;
+                            if (_value < 25) _value = 25;
+                        }
+                        else
+                        {
+                            _value = value;
+                        }
+
+                        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
+                    }
+                }
+            }
+        }
+        
+
+        [Fact]
+        public void Binding_With_Null_Path_Works()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <TextBlock Name='textBlock' Text='{Binding}'/>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var textBlock = window.FindControl<TextBlock>("textBlock");
+
+                window.DataContext = "foo";
+                window.ApplyTemplate();
+
+                Assert.Equal("foo", textBlock.Text);
+            }
+        }
+
         private class TwoWayBindingTest : Control
         {
             public static readonly StyledProperty<string> TwoWayProperty =
diff --git a/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_ElementName.cs b/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_ElementName.cs
index 40a4a6f0b3..d582964987 100644
--- a/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_ElementName.cs
+++ b/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_ElementName.cs
@@ -18,7 +18,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Data
             {
                 Child = new StackPanel
                 {
-                    Children = new Controls.Controls
+                    Children =
                     {
                         new TextBlock
                         {
@@ -54,7 +54,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Data
             {
                 Child = new StackPanel
                 {
-                    Children = new Controls.Controls
+                    Children =
                     {
                         (source = new TextBlock
                         {
@@ -89,7 +89,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Data
             {
                 Child = stackPanel = new StackPanel
                 {
-                    Children = new Controls.Controls
+                    Children =
                     {
                         (target = new TextBlock
                         {
@@ -126,7 +126,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Data
             {
                 Child = stackPanel = new StackPanel
                 {
-                    Children = new Controls.Controls
+                    Children =
                     {
                         (target = new ContentControl
                         {
diff --git a/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_Source.cs b/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_Source.cs
index c6006f3afb..1fbf8b679d 100644
--- a/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_Source.cs
+++ b/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_Source.cs
@@ -23,7 +23,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Data
 
             target.Bind(TextBlock.TextProperty, binding);
 
-            Assert.Equal(target.Text, "foo");
+            Assert.Equal("foo", target.Text);
         }
         
         public class Source : INotifyPropertyChanged
diff --git a/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_TemplatedParent.cs b/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_TemplatedParent.cs
index 197afe46ee..ccb13039f1 100644
--- a/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_TemplatedParent.cs
+++ b/tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_TemplatedParent.cs
@@ -11,6 +11,9 @@ using Avalonia.Markup.Xaml.Data;
 using Avalonia.Styling;
 using Xunit;
 using System.Reactive.Disposables;
+using Avalonia.UnitTests;
+using Avalonia.VisualTree;
+using System.Linq;
 
 namespace Avalonia.Markup.Xaml.UnitTests.Data
 {
@@ -56,6 +59,35 @@ namespace Avalonia.Markup.Xaml.UnitTests.Data
                 BindingPriority.TemplatedParent));
         }
 
+        [Fact]
+        public void TemplateBinding_With_Null_Path_Works()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <Button Name='button'>
+       <Button.Template>
+         <ControlTemplate>
+           <TextBlock Text='{TemplateBinding}'/>
+         </ControlTemplate>
+       </Button.Template>
+    </Button>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var button = window.FindControl<Button>("button");
+
+                window.ApplyTemplate();
+                button.ApplyTemplate();
+
+                var textBlock = (TextBlock)button.GetVisualChildren().Single();
+                Assert.Equal("Avalonia.Controls.Button", textBlock.Text);
+            }
+        }
+
         private Mock<IControl> CreateTarget(
             ITemplatedControl templatedParent = null,
             string text = null)
diff --git a/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/BasicTests.cs b/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/BasicTests.cs
index 03dc5374e0..fb432c30d4 100644
--- a/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/BasicTests.cs
+++ b/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/BasicTests.cs
@@ -79,6 +79,20 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
             Assert.Equal(21.0, TextBlock.GetFontSize(target));
         }
 
+        [Fact]
+        public void Attached_Property_With_Namespace_Is_Set()
+        {
+            var xaml =
+                @"<ContentControl xmlns='https://github.com/avaloniaui' 
+                    xmlns:test='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'
+                    test:BasicTestsAttachedPropertyHolder.Foo='Bar'/>";
+
+            var target = AvaloniaXamlLoader.Parse<ContentControl>(xaml);
+
+            Assert.NotNull(target);
+            Assert.Equal("Bar", BasicTestsAttachedPropertyHolder.GetFoo(target));
+        }
+
         [Fact]
         public void Attached_Property_Supports_Binding()
         {
@@ -105,7 +119,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
 
             var target = AvaloniaXamlLoader.Parse<Panel>(xaml);
 
-            Assert.Equal(0, target.Children.Count);
+            Assert.Empty(target.Children);
 
             Assert.Equal("Foo", ToolTip.GetTip(target));
         }
@@ -363,7 +377,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
 
             var styles = AvaloniaXamlLoader.Parse<Styles>(xaml);
 
-            Assert.Equal(1, styles.Count);
+            Assert.Single(styles);
 
             var style = (Style)styles[0];
 
@@ -391,13 +405,13 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
 
             var styles = AvaloniaXamlLoader.Parse<Styles>(xaml);
 
-            Assert.Equal(1, styles.Count);
+            Assert.Single(styles);
 
             var style = (Style)styles[0];
 
             var setters = style.Setters.Cast<Setter>().ToArray();
 
-            Assert.Equal(1, setters.Length);
+            Assert.Single(setters);
 
             Assert.Equal(TextBlock.FontSizeProperty, setters[0].Property);
             Assert.Equal(21.0, setters[0].Value);
@@ -445,7 +459,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
 ";
                 var styles = AvaloniaXamlLoader.Parse<Styles>(xaml);
 
-                Assert.Equal(1, styles.Count);
+                Assert.Single(styles);
 
                 var style = (Style)styles[0];
 
@@ -674,7 +688,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
 
             var style = AvaloniaXamlLoader.Parse<Style>(xaml);
 
-            Assert.Equal(1, style.Setters.Count());
+            Assert.Single(style.Setters);
 
             var setter = (Setter)style.Setters.First();
 
@@ -854,6 +868,25 @@ do we need it?")]
             }
         }
 
+        [Fact]
+        public void Element_Whitespace_Should_Be_Trimmed()
+        {
+            using (UnitTestApplication.Start(TestServices.MockWindowingPlatform))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'>
+    <TextBlock>
+        Hello World!
+    </TextBlock>
+</Window>";
+
+                var window = AvaloniaXamlLoader.Parse<Window>(xaml);
+                var textBlock = (TextBlock)window.Content;
+
+                Assert.Equal("Hello World!", textBlock.Text);
+            }
+        }
+
         private class SelectedItemsViewModel : INotifyPropertyChanged
         {
             public string[] Items { get; set; }
@@ -873,4 +906,13 @@ do we need it?")]
             }
         }
     }
+    public class BasicTestsAttachedPropertyHolder
+    {
+        public static AvaloniaProperty<string> FooProperty =
+            AvaloniaProperty.RegisterAttached<BasicTestsAttachedPropertyHolder, AvaloniaObject, string>("Foo");
+
+        public static void SetFoo(AvaloniaObject target, string value) => target.SetValue(FooProperty, value);
+        public static string GetFoo(AvaloniaObject target) => (string)target.GetValue(FooProperty);
+
+    }
 }
\ No newline at end of file
diff --git a/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/BindingTests_RelativeSource.cs b/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/BindingTests_RelativeSource.cs
index 9125e1e643..095aae7742 100644
--- a/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/BindingTests_RelativeSource.cs
+++ b/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/BindingTests_RelativeSource.cs
@@ -3,6 +3,7 @@
 
 using Avalonia.Controls;
 using Avalonia.UnitTests;
+using System;
 using Xunit;
 
 namespace Avalonia.Markup.Xaml.UnitTests.Xaml
@@ -77,6 +78,77 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
             }
         }
 
+        [Fact]
+        public void Binding_To_First_Ancestor_Without_AncestorType_Throws_Exception()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <Border Name='border1'>
+      <ContentControl Name='contentControl'>
+        <Button Name='button' Content='{Binding Name, RelativeSource={RelativeSource AncestorLevel=1}}'/>
+      </ContentControl>
+    </Border>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                Assert.Throws<InvalidOperationException>( () => loader.Load(xaml));
+            }
+        }
+
+        [Fact]
+        public void Binding_To_First_Ancestor_With_Shorthand_Works()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <Border Name='border1'>
+      <Border Name='border2'>
+        <Button Name='button' Content='{Binding $parent.Name}'/>
+      </Border>
+    </Border>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var button = window.FindControl<Button>("button");
+
+                window.ApplyTemplate();
+
+                Assert.Equal("border2", button.Content);
+            }
+        }
+
+        [Fact]
+        public void Binding_To_First_Ancestor_With_Shorthand_Uses_LogicalTree()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <Border Name='border'>
+      <ContentControl Name='contentControl'>
+        <Button Name='button' Content='{Binding $parent.Name}'/>
+      </ContentControl>
+    </Border>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var contentControl = window.FindControl<ContentControl>("contentControl");
+                var button = window.FindControl<Button>("button");
+
+                window.ApplyTemplate();
+                
+                Assert.Equal("contentControl", button.Content);
+            }
+        }
+
         [Fact]
         public void Binding_To_Second_Ancestor_Works()
         {
@@ -102,6 +174,108 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
             }
         }
 
+        [Fact]
+        public void Binding_To_Second_Ancestor_With_Shorthand_Uses_LogicalTree()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <ContentControl Name='contentControl1'>
+      <ContentControl Name='contentControl2'>
+        <Button Name='button' Content='{Binding $parent[1].Name}'/>
+      </ContentControl>
+    </ContentControl>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var contentControl1 = window.FindControl<ContentControl>("contentControl1");
+                var contentControl2 = window.FindControl<ContentControl>("contentControl2");
+                var button = window.FindControl<Button>("button");
+
+                window.ApplyTemplate();
+
+                Assert.Equal("contentControl1", button.Content);
+            }
+        }
+
+        [Fact]
+        public void Binding_To_Ancestor_Of_Type_With_Shorthand_Works()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <Border Name='border1'>
+      <Border Name='border2'>
+        <Button Name='button' Content='{Binding $parent[Border].Name}'/>
+      </Border>
+    </Border>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var button = window.FindControl<Button>("button");
+
+                window.ApplyTemplate();
+
+                Assert.Equal("border2", button.Content);
+            }
+        }
+
+        [Fact]
+        public void Binding_To_Second_Ancestor_With_Shorthand_And_Type_Works()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <Border Name='border1'>
+      <Border Name='border2'>
+        <Button Name='button' Content='{Binding $parent[Border; 1].Name}'/>
+      </Border>
+    </Border>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var button = window.FindControl<Button>("button");
+
+                window.ApplyTemplate();
+
+                Assert.Equal("border1", button.Content);
+            }
+        }
+
+        [Fact]
+        public void Binding_To_Second_Ancestor_With_Shorthand_Works()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <Border Name='border1'>
+      <Border Name='border2'>
+        <Button Name='button' Content='{Binding $parent[1].Name}'/>
+      </Border>
+    </Border>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var button = window.FindControl<Button>("button");
+
+                window.ApplyTemplate();
+
+                Assert.Equal("border1", button.Content);
+            }
+        }
+
         [Fact]
         public void Binding_To_Ancestor_With_Namespace_Works()
         {
diff --git a/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/StyleTests.cs b/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/StyleTests.cs
index b339972029..f1f4792d34 100644
--- a/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/StyleTests.cs
+++ b/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/StyleTests.cs
@@ -76,7 +76,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
 
                 var window = AvaloniaXamlLoader.Parse<ContentControl>(xaml);
 
-                Assert.Equal(1, window.Styles.Count);
+                Assert.Single(window.Styles);
 
                 var styleInclude = window.Styles[0] as StyleInclude;
 
diff --git a/tests/Avalonia.RenderTests/GeometryClippingTests.cs b/tests/Avalonia.RenderTests/GeometryClippingTests.cs
index 01af638e6d..7a01c308a4 100644
--- a/tests/Avalonia.RenderTests/GeometryClippingTests.cs
+++ b/tests/Avalonia.RenderTests/GeometryClippingTests.cs
@@ -29,7 +29,7 @@ namespace Avalonia.Direct2D1.RenderTests
                 Clip = StreamGeometry.Parse("F1 M 0,0  H 76 V 76 Z"),
                 Width = 76,
                 Height = 76,
-                Children = new Avalonia.Controls.Controls
+                Children =
                 {
                     new Path
                     {
diff --git a/tests/Avalonia.RenderTests/Media/VisualBrushTests.cs b/tests/Avalonia.RenderTests/Media/VisualBrushTests.cs
index 60589f6a00..099b022862 100644
--- a/tests/Avalonia.RenderTests/Media/VisualBrushTests.cs
+++ b/tests/Avalonia.RenderTests/Media/VisualBrushTests.cs
@@ -33,7 +33,7 @@ namespace Avalonia.Direct2D1.RenderTests.Media
             {
                 return new Panel
                 {
-                    Children = new Avalonia.Controls.Controls
+                    Children =
                     {
                         new Image
                         {
diff --git a/tests/Avalonia.RenderTests/OpacityMaskTests.cs b/tests/Avalonia.RenderTests/OpacityMaskTests.cs
index b53d9a70b1..1934654c26 100644
--- a/tests/Avalonia.RenderTests/OpacityMaskTests.cs
+++ b/tests/Avalonia.RenderTests/OpacityMaskTests.cs
@@ -37,7 +37,7 @@ namespace Avalonia.Direct2D1.RenderTests
                 },
                 Width = 76,
                 Height = 76,
-                Children = new Avalonia.Controls.Controls
+                Children =
                 {
                     new Path
                     {
diff --git a/tests/Avalonia.RenderTests/SVGPathTests.cs b/tests/Avalonia.RenderTests/SVGPathTests.cs
index d1ed0ae1cf..3d0275c072 100644
--- a/tests/Avalonia.RenderTests/SVGPathTests.cs
+++ b/tests/Avalonia.RenderTests/SVGPathTests.cs
@@ -30,7 +30,7 @@ namespace Avalonia.Direct2D1.RenderTests
                 Background = Brushes.Yellow,
                 Width = 76,
                 Height = 76,
-                Children = new Avalonia.Controls.Controls
+                Children =
                 {
                     new Path
                     {
diff --git a/tests/Avalonia.Styling.UnitTests/SelectorTests_Child.cs b/tests/Avalonia.Styling.UnitTests/SelectorTests_Child.cs
index 352efe5358..d837f2cb2f 100644
--- a/tests/Avalonia.Styling.UnitTests/SelectorTests_Child.cs
+++ b/tests/Avalonia.Styling.UnitTests/SelectorTests_Child.cs
@@ -135,6 +135,11 @@ namespace Avalonia.Styling.UnitTests
                 throw new NotImplementedException();
             }
 
+            public bool IsAnimating(AvaloniaProperty property)
+            {
+                throw new NotImplementedException();
+            }
+
             public bool IsSet(AvaloniaProperty property)
             {
                 throw new NotImplementedException();
diff --git a/tests/Avalonia.Styling.UnitTests/SelectorTests_Descendent.cs b/tests/Avalonia.Styling.UnitTests/SelectorTests_Descendent.cs
index c413904c8f..b75b59c212 100644
--- a/tests/Avalonia.Styling.UnitTests/SelectorTests_Descendent.cs
+++ b/tests/Avalonia.Styling.UnitTests/SelectorTests_Descendent.cs
@@ -165,6 +165,11 @@ namespace Avalonia.Styling.UnitTests
                 throw new NotImplementedException();
             }
 
+            public bool IsAnimating(AvaloniaProperty property)
+            {
+                throw new NotImplementedException();
+            }
+
             public bool IsSet(AvaloniaProperty property)
             {
                 throw new NotImplementedException();
diff --git a/tests/Avalonia.Styling.UnitTests/SelectorTests_Template.cs b/tests/Avalonia.Styling.UnitTests/SelectorTests_Template.cs
index 43f30f8e4d..5c34479eb2 100644
--- a/tests/Avalonia.Styling.UnitTests/SelectorTests_Template.cs
+++ b/tests/Avalonia.Styling.UnitTests/SelectorTests_Template.cs
@@ -133,7 +133,7 @@ namespace Avalonia.Styling.UnitTests
 
             using (activator.Subscribe(_ => { }))
             {
-                Assert.Equal(1, inccDebug.GetCollectionChangedSubscribers().Length);
+                Assert.Single(inccDebug.GetCollectionChangedSubscribers());
             }
 
             Assert.Null(inccDebug.GetCollectionChangedSubscribers());
diff --git a/tests/Avalonia.Styling.UnitTests/SetterTests.cs b/tests/Avalonia.Styling.UnitTests/SetterTests.cs
index b65b8dcc68..f376df4d0b 100644
--- a/tests/Avalonia.Styling.UnitTests/SetterTests.cs
+++ b/tests/Avalonia.Styling.UnitTests/SetterTests.cs
@@ -86,6 +86,77 @@ namespace Avalonia.Styling.UnitTests
             Assert.Null(control.Tag);
         }
 
+        [Fact]
+        public void Setter_Should_Apply_Value_Without_Activator_With_Style_Priority()
+        {
+            var control = new Mock<IStyleable>();
+            var style = Mock.Of<Style>();
+            var setter = new Setter(TextBlock.TextProperty, "foo");
+
+            setter.Apply(style, control.Object, null);
+
+            control.Verify(x => x.Bind(
+                TextBlock.TextProperty,
+                It.IsAny<IObservable<object>>(),
+                BindingPriority.Style));
+        }
+
+        [Fact]
+        public void Setter_Should_Apply_Value_With_Activator_With_StyleTrigger_Priority()
+        {
+            var control = new Mock<IStyleable>();
+            var style = Mock.Of<Style>();
+            var setter = new Setter(TextBlock.TextProperty, "foo");
+            var activator = new Subject<bool>();
+
+            setter.Apply(style, control.Object, activator);
+
+            control.Verify(x => x.Bind(
+                TextBlock.TextProperty,
+                It.IsAny<IObservable<object>>(),
+                BindingPriority.StyleTrigger));
+        }
+
+        [Fact]
+        public void Setter_Should_Apply_Binding_Without_Activator_With_Style_Priority()
+        {
+            var control = new Mock<IStyleable>();
+            var style = Mock.Of<Style>();
+            var setter = new Setter(TextBlock.TextProperty, CreateMockBinding(TextBlock.TextProperty));
+
+            setter.Apply(style, control.Object, null);
+
+            control.Verify(x => x.Bind(
+                TextBlock.TextProperty,
+                It.IsAny<IObservable<object>>(),
+                BindingPriority.Style));
+        }
+
+        [Fact]
+        public void Setter_Should_Apply_Binding_With_Activator_With_StyleTrigger_Priority()
+        {
+            var control = new Mock<IStyleable>();
+            var style = Mock.Of<Style>();
+            var setter = new Setter(TextBlock.TextProperty, CreateMockBinding(TextBlock.TextProperty));
+            var activator = new Subject<bool>();
+
+            setter.Apply(style, control.Object, activator);
+
+            control.Verify(x => x.Bind(
+                TextBlock.TextProperty,
+                It.IsAny<IObservable<object>>(),
+                BindingPriority.StyleTrigger));
+        }
+
+        private IBinding CreateMockBinding(AvaloniaProperty property)
+        {
+            var subject = new Subject<object>();
+            var descriptor = InstancedBinding.OneWay(subject);
+            var binding = Mock.Of<IBinding>(x => 
+                x.Initiate(It.IsAny<IAvaloniaObject>(), property, null, false) == descriptor);
+            return binding;
+        }
+
         private class TestConverter : IValueConverter
         {
             public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
diff --git a/tests/Avalonia.Styling.UnitTests/TestControlBase.cs b/tests/Avalonia.Styling.UnitTests/TestControlBase.cs
index f57ac836fb..82be755a39 100644
--- a/tests/Avalonia.Styling.UnitTests/TestControlBase.cs
+++ b/tests/Avalonia.Styling.UnitTests/TestControlBase.cs
@@ -59,6 +59,11 @@ namespace Avalonia.Styling.UnitTests
             throw new NotImplementedException();
         }
 
+        public bool IsAnimating(AvaloniaProperty property)
+        {
+            throw new NotImplementedException();
+        }
+
         public bool IsSet(AvaloniaProperty property)
         {
             throw new NotImplementedException();
diff --git a/tests/Avalonia.Styling.UnitTests/TestTemplatedControl.cs b/tests/Avalonia.Styling.UnitTests/TestTemplatedControl.cs
index 07a988f410..03b2f03bf2 100644
--- a/tests/Avalonia.Styling.UnitTests/TestTemplatedControl.cs
+++ b/tests/Avalonia.Styling.UnitTests/TestTemplatedControl.cs
@@ -67,6 +67,11 @@ namespace Avalonia.Styling.UnitTests
             throw new NotImplementedException();
         }
 
+        public bool IsAnimating(AvaloniaProperty property)
+        {
+            throw new NotImplementedException();
+        }
+
         public bool IsSet(AvaloniaProperty property)
         {
             throw new NotImplementedException();
diff --git a/tests/Avalonia.UnitTests/TestRoot.cs b/tests/Avalonia.UnitTests/TestRoot.cs
index 9ec053f075..dc137e3533 100644
--- a/tests/Avalonia.UnitTests/TestRoot.cs
+++ b/tests/Avalonia.UnitTests/TestRoot.cs
@@ -16,8 +16,6 @@ namespace Avalonia.UnitTests
     public class TestRoot : Decorator, IFocusScope, ILayoutRoot, IInputRoot, INameScope, IRenderRoot, IStyleRoot
     {
         private readonly NameScope _nameScope = new NameScope();
-        private readonly IRenderTarget _renderTarget = Mock.Of<IRenderTarget>(
-            x => x.CreateDrawingContext(It.IsAny<IVisualBrushRenderer>()) == Mock.Of<IDrawingContextImpl>());
 
         public TestRoot()
         {
@@ -65,7 +63,21 @@ namespace Avalonia.UnitTests
 
         IStyleHost IStyleHost.StylingParent => StylingParent;
 
-        public IRenderTarget CreateRenderTarget() => _renderTarget;
+        public IRenderTarget CreateRenderTarget()
+        {
+            var dc = new Mock<IDrawingContextImpl>();
+            dc.Setup(x => x.CreateLayer(It.IsAny<Size>())).Returns(() =>
+            {
+                var layerDc = new Mock<IDrawingContextImpl>();
+                var layer = new Mock<IRenderTargetBitmapImpl>();
+                layer.Setup(x => x.CreateDrawingContext(It.IsAny<IVisualBrushRenderer>())).Returns(layerDc.Object);
+                return layer.Object;
+            });
+
+            var result = new Mock<IRenderTarget>();
+            result.Setup(x => x.CreateDrawingContext(It.IsAny<IVisualBrushRenderer>())).Returns(dc.Object);
+            return result.Object;
+        }
 
         public void Invalidate(Rect rect)
         {
diff --git a/tests/Avalonia.Visuals.UnitTests/RenderTests_Culling.cs b/tests/Avalonia.Visuals.UnitTests/RenderTests_Culling.cs
index bcb5250be6..b87e72516b 100644
--- a/tests/Avalonia.Visuals.UnitTests/RenderTests_Culling.cs
+++ b/tests/Avalonia.Visuals.UnitTests/RenderTests_Culling.cs
@@ -21,7 +21,7 @@ namespace Avalonia.Visuals.UnitTests
                 Width = 100,
                 Height = 100,
                 ClipToBounds = true,
-                Children = new Controls.Controls
+                Children =
                 {
                     (target = new TestControl
                     {
@@ -47,7 +47,7 @@ namespace Avalonia.Visuals.UnitTests
                 Width = 100,
                 Height = 100,
                 ClipToBounds = true,
-                Children = new Controls.Controls
+                Children =
                 {
                     (target = new TestControl
                     {
@@ -74,7 +74,7 @@ namespace Avalonia.Visuals.UnitTests
                 Width = 100,
                 Height = 100,
                 ClipToBounds = true,
-                Children = new Controls.Controls
+                Children =
                 {
                     new Canvas
                     {
@@ -82,7 +82,7 @@ namespace Avalonia.Visuals.UnitTests
                         Height = 100,
                         [Canvas.LeftProperty] = 50,
                         [Canvas.TopProperty] = 50,
-                        Children = new Controls.Controls
+                        Children =
                         {
                             (target = new TestControl
                             {
@@ -111,7 +111,7 @@ namespace Avalonia.Visuals.UnitTests
                 Width = 100,
                 Height = 100,
                 ClipToBounds = true,
-                Children = new Controls.Controls
+                Children =
                 {
                     (target = new TestControl
                     {
@@ -138,7 +138,7 @@ namespace Avalonia.Visuals.UnitTests
                 Width = 100,
                 Height = 100,
                 ClipToBounds = true,
-                Children = new Controls.Controls
+                Children =
                 {
                     new Border
                     {
diff --git a/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs b/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs
index cec95d4807..c97070a2aa 100644
--- a/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs
@@ -1,7 +1,9 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reactive.Subjects;
 using Avalonia.Controls;
+using Avalonia.Data;
 using Avalonia.Media;
 using Avalonia.Platform;
 using Avalonia.Rendering;
@@ -19,28 +21,18 @@ namespace Avalonia.Visuals.UnitTests.Rendering
         [Fact]
         public void First_Frame_Calls_UpdateScene_On_Dispatcher()
         {
-            var loop = new Mock<IRenderLoop>();
             var root = new TestRoot();
 
             var dispatcher = new Mock<IDispatcher>();
             dispatcher.Setup(x => x.InvokeAsync(It.IsAny<Action>(), DispatcherPriority.Render))
                 .Callback<Action, DispatcherPriority>((a, p) => a());
 
-            var target = new DeferredRenderer(
-                root,
-                loop.Object,
-                sceneBuilder: MockSceneBuilder(root).Object,
-                dispatcher: dispatcher.Object);
+            CreateTargetAndRunFrame(root, dispatcher: dispatcher.Object);
 
-            target.Start();
-            RunFrame(loop);
-
-#if !NETCOREAPP1_1 // Delegate.Method is not available in netcoreapp1.1
             dispatcher.Verify(x => 
                 x.InvokeAsync(
                     It.Is<Action>(a => a.Method.Name == "UpdateScene"),
                     DispatcherPriority.Render));
-#endif
         }
 
         [Fact]
@@ -49,15 +41,8 @@ namespace Avalonia.Visuals.UnitTests.Rendering
             var loop = new Mock<IRenderLoop>();
             var root = new TestRoot();
             var sceneBuilder = MockSceneBuilder(root);
-            var dispatcher = new ImmediateDispatcher();
-            var target = new DeferredRenderer(
-                root,
-                loop.Object,
-                sceneBuilder: sceneBuilder.Object,
-                dispatcher: dispatcher);
 
-            target.Start();
-            RunFrame(loop);
+            CreateTargetAndRunFrame(root, sceneBuilder: sceneBuilder.Object);
 
             sceneBuilder.Verify(x => x.UpdateAll(It.IsAny<Scene>()));
         }
@@ -68,12 +53,10 @@ namespace Avalonia.Visuals.UnitTests.Rendering
             var loop = new Mock<IRenderLoop>();
             var root = new TestRoot();
             var sceneBuilder = MockSceneBuilder(root);
-            var dispatcher = new ImmediateDispatcher();
             var target = new DeferredRenderer(
                 root,
                 loop.Object,
-                sceneBuilder: sceneBuilder.Object,
-                dispatcher: dispatcher);
+                sceneBuilder: sceneBuilder.Object);
 
             target.Start();
             IgnoreFirstFrame(loop, sceneBuilder);
@@ -127,12 +110,93 @@ namespace Avalonia.Visuals.UnitTests.Rendering
         }
 
         [Fact]
-        public void Frame_Should_Create_Layer_For_Root()
+        public void Should_Push_Opacity_For_Controls_With_Less_Than_1_Opacity()
+        {
+            var root = new TestRoot
+            {
+                Width = 100,
+                Height = 100,
+                Child = new Border
+                {
+                    Background = Brushes.Red,
+                    Opacity = 0.5,
+                }
+            };
+
+            root.Measure(Size.Infinity);
+            root.Arrange(new Rect(root.DesiredSize));
+
+            var target = CreateTargetAndRunFrame(root);
+            var context = GetLayerContext(target, root);
+            var animation = new BehaviorSubject<double>(0.5);
+
+            context.Verify(x => x.PushOpacity(0.5), Times.Once);
+            context.Verify(x => x.FillRectangle(Brushes.Red, new Rect(0, 0, 100, 100), 0), Times.Once);
+            context.Verify(x => x.PopOpacity(), Times.Once);
+        }
+
+        [Fact]
+        public void Should_Not_Draw_Controls_With_0_Opacity()
+        {
+            var root = new TestRoot
+            {
+                Width = 100,
+                Height = 100,
+                Child = new Border
+                {
+                    Background = Brushes.Red,
+                    Opacity = 0,
+                    Child = new Border
+                    {
+                        Background = Brushes.Green,
+                    }
+                }
+            };
+
+            root.Measure(Size.Infinity);
+            root.Arrange(new Rect(root.DesiredSize));
+
+            var target = CreateTargetAndRunFrame(root);
+            var context = GetLayerContext(target, root);
+            var animation = new BehaviorSubject<double>(0.5);
+
+            context.Verify(x => x.PushOpacity(0.5), Times.Never);
+            context.Verify(x => x.FillRectangle(Brushes.Red, new Rect(0, 0, 100, 100), 0), Times.Never);
+            context.Verify(x => x.PopOpacity(), Times.Never);
+        }
+
+        [Fact]
+        public void Should_Push_Opacity_Mask()
+        {
+            var root = new TestRoot
+            {
+                Width = 100,
+                Height = 100,
+                Child = new Border
+                {
+                    Background = Brushes.Red,
+                    OpacityMask = Brushes.Green,
+                }
+            };
+
+            root.Measure(Size.Infinity);
+            root.Arrange(new Rect(root.DesiredSize));
+
+            var target = CreateTargetAndRunFrame(root);
+            var context = GetLayerContext(target, root);
+            var animation = new BehaviorSubject<double>(0.5);
+
+            context.Verify(x => x.PushOpacityMask(Brushes.Green, new Rect(0, 0, 100, 100)), Times.Once);
+            context.Verify(x => x.FillRectangle(Brushes.Red, new Rect(0, 0, 100, 100), 0), Times.Once);
+            context.Verify(x => x.PopOpacityMask(), Times.Once);
+        }
+
+        [Fact]
+        public void Should_Create_Layer_For_Root()
         {
             var loop = new Mock<IRenderLoop>();
             var root = new TestRoot();
             var rootLayer = new Mock<IRenderTargetBitmapImpl>();
-            var dispatcher = new ImmediateDispatcher();
 
             var sceneBuilder = new Mock<ISceneBuilder>();
             sceneBuilder.Setup(x => x.UpdateAll(It.IsAny<Scene>()))
@@ -143,23 +207,53 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                 });
 
             var renderInterface = new Mock<IPlatformRenderInterface>();
+            var target = CreateTargetAndRunFrame(root, sceneBuilder: sceneBuilder.Object);
 
-            var target = new DeferredRenderer(
-                root,
-                loop.Object,
-                sceneBuilder: sceneBuilder.Object,
-                //layerFactory: layers.Object,
-                dispatcher: dispatcher);
+            Assert.Single(target.Layers);
+        }
 
-            target.Start();
+        [Fact]
+        public void Should_Create_And_Delete_Layers_For_Controls_With_Animated_Opacity()
+        {
+            Border border;
+            var root = new TestRoot
+            {
+                Width = 100,
+                Height = 100,
+                Child = new Border
+                {
+                    Background = Brushes.Red,
+                    Child = border = new Border
+                    {
+                        Background = Brushes.Green,
+                        Child = new Canvas(),
+                        Opacity = 0.9,
+                    }
+                }
+            };
+
+            root.Measure(Size.Infinity);
+            root.Arrange(new Rect(root.DesiredSize));
+
+            var loop = new Mock<IRenderLoop>();
+            var target = CreateTargetAndRunFrame(root, loop: loop);
+
+            Assert.Equal(new[] { root }, target.Layers.Select(x => x.LayerRoot));
+
+            var animation = new BehaviorSubject<double>(0.5);
+            border.Bind(Border.OpacityProperty, animation, BindingPriority.Animation);
             RunFrame(loop);
 
-            var context = Mock.Get(root.CreateRenderTarget().CreateDrawingContext(null));
-            context.Verify(x => x.CreateLayer(root.ClientSize));
+            Assert.Equal(new IVisual[] { root, border }, target.Layers.Select(x => x.LayerRoot));
+
+            animation.OnCompleted();
+            RunFrame(loop);
+
+            Assert.Equal(new[] { root }, target.Layers.Select(x => x.LayerRoot));
         }
 
         [Fact]
-        public void Should_Create_And_Delete_Layers_For_Transparent_Controls()
+        public void Should_Not_Create_Layer_For_Childless_Control_With_Animated_Opacity()
         {
             Border border;
             var root = new TestRoot
@@ -176,51 +270,96 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                 }
             };
 
+            var animation = new BehaviorSubject<double>(0.5);
+            border.Bind(Border.OpacityProperty, animation, BindingPriority.Animation);
+
             root.Measure(Size.Infinity);
             root.Arrange(new Rect(root.DesiredSize));
 
-            var rootLayer = CreateLayer();
-            var borderLayer = CreateLayer();
-            var renderTargetContext = Mock.Get(root.CreateRenderTarget().CreateDrawingContext(null));
-            renderTargetContext.SetupSequence(x => x.CreateLayer(It.IsAny<Size>()))
-                .Returns(rootLayer)
-                .Returns(borderLayer);
-
             var loop = new Mock<IRenderLoop>();
-            var target = new DeferredRenderer(
-                root,
-                loop.Object,
-                dispatcher: new ImmediateDispatcher());
-            root.Renderer = target;
+            var target = CreateTargetAndRunFrame(root, loop: loop);
 
-            target.Start();
-            RunFrame(loop);
+            Assert.Single(target.Layers);
+        }
+
+        [Fact]
+        public void Should_Not_Push_Opacity_For_Transparent_Layer_Root_Control()
+        {
+            Border border;
+            var root = new TestRoot
+            {
+                Width = 100,
+                Height = 100,
+                Child = border = new Border
+                {
+                    Background = Brushes.Red,
+                    Child = new Canvas(),
+                }
+            };
+
+            var animation = new BehaviorSubject<double>(0.5);
+            border.Bind(Border.OpacityProperty, animation, BindingPriority.Animation);
 
-            var rootContext = Mock.Get(rootLayer.CreateDrawingContext(null));
-            var borderContext = Mock.Get(borderLayer.CreateDrawingContext(null));
+            root.Measure(Size.Infinity);
+            root.Arrange(new Rect(root.DesiredSize));
 
-            rootContext.Verify(x => x.FillRectangle(Brushes.Red, new Rect(0, 0, 100, 100), 0), Times.Once);
-            rootContext.Verify(x => x.FillRectangle(Brushes.Green, new Rect(0, 0, 100, 100), 0), Times.Once);
-            borderContext.Verify(x => x.FillRectangle(It.IsAny<IBrush>(), It.IsAny<Rect>(), It.IsAny<float>()), Times.Never);
+            var target = CreateTargetAndRunFrame(root);
+            var context = GetLayerContext(target, border);
 
-            rootContext.ResetCalls();
-            borderContext.ResetCalls();
-            border.Opacity = 0.5;
-            RunFrame(loop);
+            context.Verify(x => x.PushOpacity(0.5), Times.Never);
+            context.Verify(x => x.FillRectangle(Brushes.Red, new Rect(0, 0, 100, 100), 0), Times.Once);
+            context.Verify(x => x.PopOpacity(), Times.Never);
+        }
+
+        [Fact]
+        public void Should_Draw_Transparent_Layer_With_Correct_Opacity()
+        {
+            Border border;
+            var root = new TestRoot
+            {
+                Width = 100,
+                Height = 100,
+                Child = border = new Border
+                {
+                    Background = Brushes.Red,
+                    Child = new Canvas(),
+                }
+            };
+
+            var animation = new BehaviorSubject<double>(0.5);
+            border.Bind(Border.OpacityProperty, animation, BindingPriority.Animation);
+
+            root.Measure(Size.Infinity);
+            root.Arrange(new Rect(root.DesiredSize));
 
-            rootContext.Verify(x => x.FillRectangle(Brushes.Red, new Rect(0, 0, 100, 100), 0), Times.Once);
-            rootContext.Verify(x => x.FillRectangle(Brushes.Green, new Rect(0, 0, 100, 100), 0), Times.Never);
-            borderContext.Verify(x => x.FillRectangle(Brushes.Green, new Rect(0, 0, 100, 100), 0), Times.Once);
+            var target = CreateTargetAndRunFrame(root);
+            var context = Mock.Get(target.RenderTarget.CreateDrawingContext(null));
+            var borderLayer = target.Layers[border].Bitmap;
 
-            rootContext.ResetCalls();
-            borderContext.ResetCalls();
-            border.Opacity = 1;
+            context.Verify(x => x.DrawImage(borderLayer, 0.5, It.IsAny<Rect>(), It.IsAny<Rect>()));
+        }
+
+        private DeferredRenderer CreateTargetAndRunFrame(
+            TestRoot root,
+            Mock<IRenderLoop> loop = null,
+            ISceneBuilder sceneBuilder = null,
+            IDispatcher dispatcher = null)
+        {
+            loop = loop ?? new Mock<IRenderLoop>();
+            var target = new DeferredRenderer(
+                root,
+                loop.Object,
+                sceneBuilder: sceneBuilder,
+                dispatcher: dispatcher ?? new ImmediateDispatcher());
+            root.Renderer = target;
+            target.Start();
             RunFrame(loop);
+            return target;
+        }
 
-            Mock.Get(borderLayer).Verify(x => x.Dispose());
-            rootContext.Verify(x => x.FillRectangle(Brushes.Red, new Rect(0, 0, 100, 100), 0), Times.Once);
-            rootContext.Verify(x => x.FillRectangle(Brushes.Green, new Rect(0, 0, 100, 100), 0), Times.Once);
-            borderContext.Verify(x => x.FillRectangle(It.IsAny<IBrush>(), It.IsAny<Rect>(), It.IsAny<float>()), Times.Never);
+        private Mock<IDrawingContextImpl> GetLayerContext(DeferredRenderer renderer, IControl layerRoot)
+        {
+            return Mock.Get(renderer.Layers[layerRoot].Bitmap.CreateDrawingContext(null));
         }
 
         private void IgnoreFirstFrame(Mock<IRenderLoop> loop, Mock<ISceneBuilder> sceneBuilder)
diff --git a/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests_HitTesting.cs b/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests_HitTesting.cs
index 9e2f1fc293..3a9e45a02b 100644
--- a/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests_HitTesting.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests_HitTesting.cs
@@ -154,7 +154,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                     {
                         Width = 200,
                         Height = 200,
-                        Children = new Controls.Controls
+                        Children =
                         {
                             new Border
                             {
@@ -198,7 +198,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                     {
                         Width = 200,
                         Height = 200,
-                        Children = new Controls.Controls
+                        Children =
                         {
                             new Border
                             {
@@ -255,7 +255,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                         Height = 200,
                         Background = Brushes.Red,
                         ClipToBounds = false,
-                        Children = new Controls.Controls
+                        Children =
                         {
                             new Border
                             {
@@ -303,7 +303,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                         Width = 100,
                         Height = 200,
                         Background = Brushes.Red,
-                        Children = new Controls.Controls
+                        Children =
                         {
                             new Panel()
                             {
@@ -312,7 +312,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                                 Background = Brushes.Red,
                                 Margin = new Thickness(0, 100, 0, 0),
                                 ClipToBounds = true,
-                                Children = new Controls.Controls
+                                Children =
                                 {
                                     (target = new Border()
                                     {
@@ -354,7 +354,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                         Width = 100,
                         Height = 200,
                         Background = Brushes.Red,
-                        Children = new Controls.Controls
+                        Children =
                         {
                             (target = new Border()
                             {
@@ -374,7 +374,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                                 {
                                     Content = new StackPanel()
                                     {
-                                        Children = new Controls.Controls
+                                        Children =
                                         {
                                             (item1 = new Border()
                                             {
diff --git a/tests/Avalonia.Visuals.UnitTests/Rendering/ImmediateRendererTests_HitTesting.cs b/tests/Avalonia.Visuals.UnitTests/Rendering/ImmediateRendererTests_HitTesting.cs
index c8a19a9f46..9a1d8cb59c 100644
--- a/tests/Avalonia.Visuals.UnitTests/Rendering/ImmediateRendererTests_HitTesting.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Rendering/ImmediateRendererTests_HitTesting.cs
@@ -126,7 +126,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                     {
                         Width = 200,
                         Height = 200,
-                        Children = new Controls.Controls
+                        Children =
                         {
                             new Border
                             {
@@ -171,7 +171,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                     {
                         Width = 200,
                         Height = 200,
-                        Children = new Controls.Controls
+                        Children =
                         {
                             new Border
                             {
@@ -238,7 +238,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                         Height = 200,
                         Background = Brushes.Red,
                         ClipToBounds = false,
-                        Children = new Controls.Controls
+                        Children =
                         {
                             new Border
                             {
@@ -287,7 +287,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                         Width = 100,
                         Height = 200,
                         Background = Brushes.Red,
-                        Children = new Controls.Controls
+                        Children =
                         {
                             new Panel()
                             {
@@ -296,7 +296,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                                 Background = Brushes.Red,
                                 Margin = new Thickness(0, 100, 0, 0),
                                 ClipToBounds = true,
-                                Children = new Controls.Controls
+                                Children =
                                 {
                                     (target = new Border()
                                     {
@@ -339,7 +339,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                         Width = 100,
                         Height = 200,
                         Background = Brushes.Red,
-                        Children = new Controls.Controls
+                        Children =
                         {
                             (target = new Border()
                             {
@@ -359,7 +359,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                                 {
                                     Content = new StackPanel()
                                     {
-                                        Children = new Controls.Controls
+                                        Children =
                                         {
                                             (item1 = new Border()
                                             {
diff --git a/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests.cs b/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests.cs
index d0f7671956..44b9ebe8ce 100644
--- a/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests.cs
@@ -9,6 +9,8 @@ using Xunit;
 using Avalonia.Layout;
 using Moq;
 using Avalonia.Platform;
+using System.Reactive.Subjects;
+using Avalonia.Data;
 
 namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
 {
@@ -620,13 +622,15 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                         Margin = new Thickness(0, 10, 0, 0),
                         Child = border = new Border
                         {
-                            Opacity = 0.5,
                             Background = Brushes.Red,
                             Child = canvas = new Canvas(),
                         }
                     }
                 };
 
+                var animation = new BehaviorSubject<double>(0.5);
+                border.Bind(Border.OpacityProperty, animation, BindingPriority.Animation);
+
                 var scene = new Scene(tree);
                 var sceneBuilder = new SceneBuilder();
                 sceneBuilder.UpdateAll(scene);
diff --git a/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests_Layers.cs b/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests_Layers.cs
index e65487ac44..f2d137249a 100644
--- a/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests_Layers.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests_Layers.cs
@@ -7,14 +7,15 @@ using Avalonia.UnitTests;
 using Avalonia.VisualTree;
 using Xunit;
 using Avalonia.Layout;
-using Avalonia.Rendering;
+using System.Reactive.Subjects;
+using Avalonia.Data;
 
 namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
 {
     public partial class SceneBuilderTests
     {
         [Fact]
-        public void Control_With_Transparency_Should_Start_New_Layer()
+        public void Control_With_Animated_Opacity_And_Children_Should_Start_New_Layer()
         {
             using (TestApplication())
             {
@@ -31,10 +32,9 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                         Padding = new Thickness(11),
                         Child = border = new Border
                         {
-                            Opacity = 0.5,
                             Background = Brushes.Red,
                             Padding = new Thickness(12),
-                            Child = canvas = new Canvas(),
+                            Child = canvas = new Canvas()
                         }
                     }
                 };
@@ -42,6 +42,9 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                 var layout = AvaloniaLocator.Current.GetService<ILayoutManager>();
                 layout.ExecuteInitialLayoutPass(tree);
 
+                var animation = new BehaviorSubject<double>(0.5);
+                border.Bind(Border.OpacityProperty, animation, BindingPriority.Animation);
+
                 var scene = new Scene(tree);
                 var sceneBuilder = new SceneBuilder();
                 sceneBuilder.UpdateAll(scene);
@@ -58,7 +61,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                 Assert.Equal(2, scene.Layers.Count());
                 Assert.Empty(scene.Layers.Select(x => x.LayerRoot).Except(new IVisual[] { tree, border }));
 
-                border.Opacity = 1;
+                animation.OnCompleted();
                 scene = scene.Clone();
 
                 sceneBuilder.Update(scene, border);
@@ -70,23 +73,22 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                 Assert.Same(tree, rootNode.LayerRoot);
                 Assert.Same(tree, borderNode.LayerRoot);
                 Assert.Same(tree, canvasNode.LayerRoot);
-                Assert.Equal(1, scene.Layers.Count());
+                Assert.Single(scene.Layers);
 
                 var rootDirty = scene.Layers[tree].Dirty;
 
-                Assert.Equal(1, rootDirty.Count());
+                Assert.Single(rootDirty);
                 Assert.Equal(new Rect(21, 21, 58, 78), rootDirty.Single());
             }
         }
 
         [Fact]
-        public void Control_With_OpacityMask_Should_Start_New_Layer()
+        public void Control_With_Animated_Opacity_And_No_Children_Should_Not_Start_New_Layer()
         {
             using (TestApplication())
             {
                 Decorator decorator;
                 Border border;
-                Canvas canvas;
                 var tree = new TestRoot
                 {
                     Padding = new Thickness(10),
@@ -97,10 +99,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                         Padding = new Thickness(11),
                         Child = border = new Border
                         {
-                            OpacityMask = Brushes.Red,
                             Background = Brushes.Red,
-                            Padding = new Thickness(12),
-                            Child = canvas = new Canvas(),
                         }
                     }
                 };
@@ -108,45 +107,19 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                 var layout = AvaloniaLocator.Current.GetService<ILayoutManager>();
                 layout.ExecuteInitialLayoutPass(tree);
 
+                var animation = new BehaviorSubject<double>(0.5);
+                border.Bind(Border.OpacityProperty, animation, BindingPriority.Animation);
+
                 var scene = new Scene(tree);
                 var sceneBuilder = new SceneBuilder();
                 sceneBuilder.UpdateAll(scene);
 
-                var rootNode = (VisualNode)scene.Root;
-                var borderNode = (VisualNode)scene.FindNode(border);
-                var canvasNode = (VisualNode)scene.FindNode(canvas);
-
-                Assert.Same(tree, rootNode.LayerRoot);
-                Assert.Same(border, borderNode.LayerRoot);
-                Assert.Same(border, canvasNode.LayerRoot);
-                Assert.Equal(Brushes.Red, scene.Layers[border].OpacityMask);
-
-                Assert.Equal(2, scene.Layers.Count());
-                Assert.Empty(scene.Layers.Select(x => x.LayerRoot).Except(new IVisual[] { tree, border }));
-
-                border.OpacityMask = null;
-                scene = scene.Clone();
-
-                sceneBuilder.Update(scene, border);
-
-                rootNode = (VisualNode)scene.Root;
-                borderNode = (VisualNode)scene.FindNode(border);
-                canvasNode = (VisualNode)scene.FindNode(canvas);
-
-                Assert.Same(tree, rootNode.LayerRoot);
-                Assert.Same(tree, borderNode.LayerRoot);
-                Assert.Same(tree, canvasNode.LayerRoot);
-                Assert.Equal(1, scene.Layers.Count());
-
-                var rootDirty = scene.Layers[tree].Dirty;
-
-                Assert.Equal(1, rootDirty.Count());
-                Assert.Equal(new Rect(21, 21, 58, 78), rootDirty.Single());
+                Assert.Single(scene.Layers);
             }
         }
 
         [Fact]
-        public void Removing_Transparent_Control_Should_Remove_Layers()
+        public void Removing_Control_With_Animated_Opacity_Should_Remove_Layers()
         {
             using (TestApplication())
             {
@@ -163,13 +136,12 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                         Padding = new Thickness(11),
                         Child = border = new Border
                         {
-                            Opacity = 0.5,
                             Background = Brushes.Red,
                             Padding = new Thickness(12),
                             Child = canvas = new Canvas
                             {
-                                Opacity = 0.75,
-                            },
+                                Children = { new TextBlock() },
+                            }
                         }
                     }
                 };
@@ -177,6 +149,10 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                 var layout = AvaloniaLocator.Current.GetService<ILayoutManager>();
                 layout.ExecuteInitialLayoutPass(tree);
 
+                var animation = new BehaviorSubject<double>(0.5);
+                border.Bind(Border.OpacityProperty, animation, BindingPriority.Animation);
+                canvas.Bind(Canvas.OpacityProperty, animation, BindingPriority.Animation);
+
                 var scene = new Scene(tree);
                 var sceneBuilder = new SceneBuilder();
                 sceneBuilder.UpdateAll(scene);
@@ -210,13 +186,12 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                         Padding = new Thickness(11),
                         Child = border = new Border
                         {
-                            Opacity = 0.5,
                             Background = Brushes.Red,
                             Padding = new Thickness(12),
                             Child = canvas = new Canvas
                             {
-                                Opacity = 0.75,
-                            },
+                                Children = { new TextBlock() },
+                            }
                         }
                     }
                 };
@@ -224,6 +199,10 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                 var layout = AvaloniaLocator.Current.GetService<ILayoutManager>();
                 layout.ExecuteInitialLayoutPass(tree);
 
+                var animation = new BehaviorSubject<double>(0.5);
+                border.Bind(Border.OpacityProperty, animation, BindingPriority.Animation);
+                canvas.Bind(Canvas.OpacityProperty, animation, BindingPriority.Animation);
+
                 var scene = new Scene(tree);
                 var sceneBuilder = new SceneBuilder();
                 sceneBuilder.UpdateAll(scene);
@@ -256,6 +235,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                         Child = border = new Border
                         {
                             Opacity = 0.5,
+                            Child = new Canvas(),
                         }
                     }
                 };
@@ -263,6 +243,9 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                 var layout = AvaloniaLocator.Current.GetService<ILayoutManager>();
                 layout.ExecuteInitialLayoutPass(tree);
 
+                var animation = new BehaviorSubject<double>(0.5);
+                border.Bind(Border.OpacityProperty, animation, BindingPriority.Animation);
+
                 var scene = new Scene(tree);
                 var sceneBuilder = new SceneBuilder();
                 sceneBuilder.UpdateAll(scene);
diff --git a/tests/Avalonia.Visuals.UnitTests/VisualTests.cs b/tests/Avalonia.Visuals.UnitTests/VisualTests.cs
index f20c59fabe..b62bf5858d 100644
--- a/tests/Avalonia.Visuals.UnitTests/VisualTests.cs
+++ b/tests/Avalonia.Visuals.UnitTests/VisualTests.cs
@@ -190,7 +190,7 @@ namespace Avalonia.Visuals.UnitTests
             root1.Child = child;
 
             Assert.Throws<InvalidOperationException>(() => root2.Child = child);
-            Assert.Equal(0, root2.GetVisualChildren().Count());
+            Assert.Empty(root2.GetVisualChildren());
         }
     }
 }