diff --git a/.gitmodules b/.gitmodules
index 057007f213..daef52a069 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -8,3 +8,6 @@
 [submodule "src/Markup/Perspex.Markup.Xaml/OmniXAML"]
 	path = src/Markup/Perspex.Markup.Xaml/OmniXAML
 	url = https://github.com/Perspex/OmniXAML.git
+[submodule "src/Markup/Perspex.Markup.Xaml/glass"]
+	path = src/Markup/Perspex.Markup.Xaml/glass
+	url = https://github.com/SuperJMN/glass
diff --git a/Perspex.sln b/Perspex.sln
index 62c59b8aed..c081e1ed22 100644
--- a/Perspex.sln
+++ b/Perspex.sln
@@ -60,9 +60,6 @@ EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Perspex.Markup.Xaml", "src\Markup\Perspex.Markup.Xaml\Perspex.Markup.Xaml.csproj", "{3E53A01A-B331-47F3-B828-4A5717E77A24}"
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Samples", "Samples", "{9B9E3891-2366-4253-A952-D08BCEB71098}"
-	ProjectSection(SolutionItems) = preProject
-		samples\ControlCatalog\ControlCatalog.csproj = samples\ControlCatalog\ControlCatalog.csproj
-	EndProjectSection
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TestApplication", "samples\TestApplication\TestApplication.csproj", "{E3A1060B-50D0-44E8-88B6-F44EF2E5BD72}"
 	ProjectSection(ProjectDependencies) = postProject
diff --git a/appveyor.yml b/appveyor.yml
index 1aee6bb2cf..2cb5bf6484 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -20,6 +20,7 @@ configuration:
   - Release
 
 after_test:
+- .\packages\JetBrains.dotMemoryUnit.2.1.20150828.125449\tools\dotMemoryUnit.exe -targetExecutable="%xunit20%\xunit.console.x86.exe" -returnTargetExitCode  --"tests\Perspex.LeakTests\bin\Release\Perspex.LeakTests.dll"
 - ps: nuget\build-appveyor.ps1
 
 artifacts:
diff --git a/samples/BindingTest/MainWindow.xaml b/samples/BindingTest/MainWindow.xaml
index 94f420d5b3..9bd6a3e3a8 100644
--- a/samples/BindingTest/MainWindow.xaml
+++ b/samples/BindingTest/MainWindow.xaml
@@ -68,5 +68,14 @@
         </ContentControl>
       </StackPanel>
     </TabItem>
+    <TabItem Header="Commands">
+      <StackPanel Margin="18" Gap="4" Width="200">
+        <Button Content="Button" Command="{Binding StringValueCommand}" CommandParameter="Button"/>
+        <ToggleButton Content="ToggleButton" IsChecked="{Binding BooleanFlag, Mode=OneWay}" Command="{Binding StringValueCommand}" CommandParameter="ToggleButton"/>
+        <CheckBox Content="CheckBox" IsChecked="{Binding !BooleanFlag, Mode=OneWay}" Command="{Binding StringValueCommand}" CommandParameter="CheckBox"/>
+        <RadioButton Content="RadionButton" IsChecked="{Binding !!BooleanFlag, Mode=OneWay}" Command="{Binding StringValueCommand}" CommandParameter="RadioButton"/>
+        <TextBox Text="{Binding Path=StringValue}"/>
+      </StackPanel>
+    </TabItem>
   </TabControl>
 </Window>
\ No newline at end of file
diff --git a/samples/BindingTest/ViewModels/MainWindowViewModel.cs b/samples/BindingTest/ViewModels/MainWindowViewModel.cs
index 6df695527a..114ddf5cbf 100644
--- a/samples/BindingTest/ViewModels/MainWindowViewModel.cs
+++ b/samples/BindingTest/ViewModels/MainWindowViewModel.cs
@@ -2,6 +2,7 @@
 using System.Collections.ObjectModel;
 using System.Linq;
 using ReactiveUI;
+using System.Reactive.Linq;
 
 namespace BindingTest.ViewModels
 {
@@ -10,6 +11,7 @@ namespace BindingTest.ViewModels
         private string _booleanString = "True";
         private double _doubleValue = 5.0;
         private string _stringValue = "Simple Binding";
+        private bool _booleanFlag = false;
 
         public MainWindowViewModel()
         {
@@ -28,6 +30,13 @@ namespace BindingTest.ViewModels
                 var r = new Random();
                 Items.Move(r.Next(Items.Count), 1);
             });
+
+            StringValueCommand = ReactiveCommand.Create();
+            StringValueCommand.Subscribe(param =>
+            {
+                BooleanFlag = !BooleanFlag;
+                StringValue = param.ToString();
+            });
         }
 
         public ObservableCollection<TestItem> Items { get; }
@@ -51,5 +60,13 @@ namespace BindingTest.ViewModels
             get { return _stringValue; }
             set { this.RaiseAndSetIfChanged(ref _stringValue, value); }
         }
+
+        public bool BooleanFlag
+        {
+            get { return _booleanFlag; }
+            set { this.RaiseAndSetIfChanged(ref _booleanFlag, value); }
+        }
+
+        public ReactiveCommand<object> StringValueCommand { get; }
     }
 }
diff --git a/samples/ControlCatalog.Desktop/Program.cs b/samples/ControlCatalog.Desktop/Program.cs
index 3fa5d32ae3..3a6f466b9e 100644
--- a/samples/ControlCatalog.Desktop/Program.cs
+++ b/samples/ControlCatalog.Desktop/Program.cs
@@ -6,24 +6,6 @@ using Perspex;
 using System.Reflection;
 using Perspex.Platform;
 
-
-// Not sure where the best home for this is
-namespace Perspex
-{
-    public static class SharedApplicationExtensions
-    {
-        // For true Portable apps we need to select the PCL assembly NOT the host platform exe. Unfortunately
-        // Win32 subsystem registers one by default (the wrong one) and so this can override that.
-        //
-        public static AppT UseAssetAssembly<AppT>(this AppT app, Assembly assembly) where AppT : Application
-        {
-            // Asset loading searches our own assembly?
-            PerspexLocator.CurrentMutable.GetService<IAssetLoader>().SetDefaultAssembly(assembly);
-            return app;
-        }
-    }
-}
-
 namespace ControlCatalog
 {
     internal class Program
@@ -34,7 +16,6 @@ namespace ControlCatalog
 
             new App()
                 .ConfigureRenderSystem(args)
-                .UseAssetAssembly(typeof(App).Assembly)
                 .LoadFromXaml()
                 .RunWithMainWindow<MainWindow>();
         }
diff --git a/samples/ControlCatalog/Pages/CanvasPage.xaml b/samples/ControlCatalog/Pages/CanvasPage.xaml
index 8aaa8176bd..687a048a09 100644
--- a/samples/ControlCatalog/Pages/CanvasPage.xaml
+++ b/samples/ControlCatalog/Pages/CanvasPage.xaml
@@ -4,10 +4,22 @@
     <TextBlock Classes="h2">A panel which lays out its children by explicit coordinates</TextBlock>
     <Canvas Background="Yellow" Width="300" Height="400">
       <Rectangle Fill="Blue" Width="63" Height="41" Canvas.Left="40" Canvas.Top="31"/>
-      <Ellipse Fill="Green" Width="58" Height="58" Canvas.Left="160" Canvas.Top="79"/>
+      <Ellipse Fill="Green" Width="58" Height="58" Canvas.Left="88" Canvas.Top="100"/>
       <Path Fill="Orange" Data="M 0,0 c 50,0 50,-50 c 50,0 50,50 h -50 v 50 l -50,-50 Z" Canvas.Left="30" Canvas.Top="250"/>
+      <Path Fill="OrangeRed" Canvas.Left="180" Canvas.Top="250">
+        <Path.Data>
+          <PathGeometry>
+            <PathFigure StartPoint="0,0" IsClosed="True">
+              <QuadraticBezierSegment Point1="50,0" Point2="50,-50" />
+              <QuadraticBezierSegment Point1="100,-50" Point2="100,0" />
+              <LineSegment Point="50,0" />
+              <LineSegment Point="50,50" />
+            </PathFigure>
+          </PathGeometry>
+        </Path.Data>
+      </Path>
       <Line StartPoint="120,185" EndPoint="30,115" Stroke="Red" StrokeThickness="2"/>
-      <Polygon Points="75,0 120,120 0,45 150,45 30,120" Stroke="DarkBlue" StrokeThickness="1" Fill="Violet" Canvas.Left="150" Canvas.Top="180"/>
+      <Polygon Points="75,0 120,120 0,45 150,45 30,120" Stroke="DarkBlue" StrokeThickness="1" Fill="Violet" Canvas.Left="150" Canvas.Top="31"/>
       <Polyline Points="0,0 65,0 78,-26 91,39 104,-39 117,13 130,0 195,0" Stroke="Brown" Canvas.Left="30" Canvas.Top="350"/>
     </Canvas>
   </StackPanel>
diff --git a/samples/XamlTestApplicationPcl/ViewModels/EditorViewModel.cs b/samples/XamlTestApplicationPcl/ViewModels/EditorViewModel.cs
new file mode 100644
index 0000000000..4623a14275
--- /dev/null
+++ b/samples/XamlTestApplicationPcl/ViewModels/EditorViewModel.cs
@@ -0,0 +1,103 @@
+using Perspex.Threading;
+
+namespace XamlTestApplication.ViewModels
+{
+    using ReactiveUI;
+    using System;
+    using System.Collections.Generic;
+    using System.Collections.ObjectModel;
+    using System.Linq;
+    using System.Text;
+    using System.Threading.Tasks;
+
+    public class ShellViewModel : ReactiveObject
+    {
+        private ShellViewModel()
+        {
+            documents = new ObservableCollection<EditorViewModel>();
+
+            AddDocumentCommand = ReactiveCommand.Create();
+            AddDocumentCommand.Subscribe(_ =>
+            {
+                Documents.Add(new EditorViewModel());
+            });
+
+            GCCommand = ReactiveCommand.Create();
+            GCCommand.Subscribe(_ =>
+            {
+                GC.Collect();
+            });
+        }
+
+        public static ShellViewModel Instance = new ShellViewModel();
+
+        private ObservableCollection<EditorViewModel> documents;
+        public ObservableCollection<EditorViewModel> Documents
+        {
+            get { return documents; }
+            set { this.RaiseAndSetIfChanged(ref documents, value); }
+        }
+
+        private EditorViewModel selectedDocument;
+
+        public EditorViewModel SelectedDocument
+        {
+            get { return selectedDocument; }
+            set { this.RaiseAndSetIfChanged(ref selectedDocument, value); }
+        }
+
+        private int instanceCount;
+
+        public int InstanceCount
+        {
+            get { return instanceCount; }
+            set { this.RaiseAndSetIfChanged(ref instanceCount, value); }
+        }
+
+
+
+        public ReactiveCommand<object> AddDocumentCommand { get; }
+        public ReactiveCommand<object> GCCommand { get; }
+    }
+
+    public class EditorViewModel : ReactiveObject
+    {
+        private static int InstanceCount = 0;
+
+        public EditorViewModel()
+        {
+            InstanceCount++;
+            ShellViewModel.Instance.InstanceCount = InstanceCount;
+            text = "This is some text.";
+
+            CloseCommand = ReactiveCommand.Create();
+
+            CloseCommand.Subscribe(_ =>
+            {
+                ShellViewModel.Instance.Documents.Remove(this);
+            });
+        }
+
+        ~EditorViewModel()
+        {
+            
+            
+            //System.Console.WriteLine("EVM Destructed");
+            InstanceCount--;
+            Dispatcher.UIThread.InvokeAsync(() =>
+            {
+                ShellViewModel.Instance.InstanceCount = InstanceCount;
+            });
+
+        }
+
+        private string text;
+        public string Text
+        {
+            get { return text; }
+            set { this.RaiseAndSetIfChanged(ref text, value); }
+        }
+
+        public ReactiveCommand<object> CloseCommand { get; }
+    }
+}
diff --git a/samples/XamlTestApplicationPcl/ViewModels/MainWindowViewModel.cs b/samples/XamlTestApplicationPcl/ViewModels/MainWindowViewModel.cs
index 3ae72e138c..f584493097 100644
--- a/samples/XamlTestApplicationPcl/ViewModels/MainWindowViewModel.cs
+++ b/samples/XamlTestApplicationPcl/ViewModels/MainWindowViewModel.cs
@@ -56,7 +56,11 @@ namespace XamlTestApplication.ViewModels
                 }
             };
 
-            CollapseNodesCommand = ReactiveCommand.Create();
+            
+        
+
+
+        CollapseNodesCommand = ReactiveCommand.Create();
             CollapseNodesCommand.Subscribe(_ => ExpandNodes(false));
             ExpandNodesCommand = ReactiveCommand.Create();
             ExpandNodesCommand.Subscribe(_ => ExpandNodes(true));
@@ -77,6 +81,15 @@ namespace XamlTestApplication.ViewModels
                 ofd.ShowAsync();
             });
 
+            shell = ShellViewModel.Instance;
+        }
+
+        private ShellViewModel shell;
+
+        public ShellViewModel Shell
+        {
+            get { return shell; }
+            set { shell = value; }
         }
 
         public List<TestItem> Items { get; }
diff --git a/samples/XamlTestApplicationPcl/Views/MainWindow.xaml b/samples/XamlTestApplicationPcl/Views/MainWindow.xaml
index 1dc8575178..594f27bc41 100644
--- a/samples/XamlTestApplicationPcl/Views/MainWindow.xaml
+++ b/samples/XamlTestApplicationPcl/Views/MainWindow.xaml
@@ -316,6 +316,84 @@
           <local:TestScrollable/>
         </ScrollViewer>
       </TabItem>
+      <TabItem Header="Mem Leak Repro">
+        <Grid DataContext="{Binding Shell}">
+            <StackPanel>
+              
+            <TabStrip Name="strip"  Items="{Binding Documents}" SelectedItem="{Binding SelectedDocument, Mode=TwoWay}" Focusable="false">
+              <TabStrip.Styles>                
+
+                <Style Selector="TabStripItem">
+                  <Setter Property="Height" Value="20" />
+                  <Setter Property="Background" Value="#2D2D30" />
+                  <Setter Property="BorderBrush" Value="#3E3E42" />
+                  <Setter Property="BorderThickness" Value="0" />
+                  <Setter Property="Margin" Value="0 0 0 -1" />
+                  <Setter Property="Padding" Value="4 0 4 0" />
+                  <Setter Property="FontSize" Value="12"/>
+                </Style>
+                <Style Selector="TabStripItem:pointerover">
+                  <Setter Property="Background" Value="#1c97ea" />
+                </Style>
+                <Style Selector="TabStripItem:selected">
+                  <Setter Property="Background" Value="#007ACC" />
+                </Style>
+              </TabStrip.Styles>
+
+              <TabStrip.DataTemplates>
+                <DataTemplate>
+                  <StackPanel Orientation="Horizontal" Gap="2">                    
+                    <TextBlock Text="{Binding Title}" Foreground="WhiteSmoke" Margin="2"/>                    
+                    <Button Height="14" Width="14">
+                      <Button.Styles>
+                        <Style Selector="Button">
+                          <Setter Property="BorderThickness" Value="0"/>
+                          <Setter Property="Padding" Value="0"/>
+                          <Setter Property="Margin" Value="0"/>
+                          <Setter Property="Background" Value="Transparent" />
+                        </Style>
+
+                        <Style Selector="Button:pointerover">
+                          <Setter Property="Background" Value="#1c97ea" />
+                        </Style>
+                      </Button.Styles>
+                      <Path Margin="2" Stretch="Uniform" UseLayoutRounding="False" Data="M16,12V4H17V2H7V4H8V12L6,14V16H11.2V22H12.8V16H18V14L16,12Z" Fill="WhiteSmoke" />
+
+                    </Button>
+
+                    <Button Height="14" Width="14" Command="{Binding CloseCommand}">
+                      <Button.Styles>
+                        <Style Selector="Button">
+                          <Setter Property="BorderThickness" Value="0"/>
+                          <Setter Property="Padding" Value="0"/>
+                          <Setter Property="Margin" Value="0"/>
+                          <Setter Property="Background" Value="Transparent" />
+                        </Style>
+                        <Style Selector="Button:pointerover">
+                          <Setter Property="Background" Value="#1c97ea" />
+                        </Style>
+                      </Button.Styles>
+                      <Path Margin="2" Stretch="Uniform" UseLayoutRounding="False" Data="M19,6.41L17.59,5L12,10.59L6.41,5L5,6.41L10.59,12L5,17.59L6.41,19L12,13.41L17.59,19L19,17.59L13.41,12L19,6.41Z" Fill="WhiteSmoke" />
+                    </Button>
+                  </StackPanel>                  
+                </DataTemplate>
+              </TabStrip.DataTemplates>
+            </TabStrip>
+            <Grid Background="#007ACC" Height="2" />
+              <Button Content="AddTab" Command="{Binding AddDocumentCommand}" Width="50" Height="30" />
+              <Button Content="GC.Collecy" Command="{Binding GCCommand}" Width="50" Height="30" />
+              <TextBox Text="{Binding InstanceCount}"           />
+
+          <Carousel Items="{Binding Documents}" SelectedIndex="{Binding #strip.SelectedIndex}" IsVirtualized="false">
+            <Carousel.DataTemplates>
+              <DataTemplate>
+                <TextBox Text="{Binding Text}" />
+              </DataTemplate>
+            </Carousel.DataTemplates>
+          </Carousel>
+            </StackPanel>
+        </Grid>
+      </TabItem>
     </TabControl>
   </Grid>
 </Window>
\ No newline at end of file
diff --git a/samples/XamlTestApplicationPcl/XamlTestApplicationPcl.csproj b/samples/XamlTestApplicationPcl/XamlTestApplicationPcl.csproj
index 6d15fea543..07e907e155 100644
--- a/samples/XamlTestApplicationPcl/XamlTestApplicationPcl.csproj
+++ b/samples/XamlTestApplicationPcl/XamlTestApplicationPcl.csproj
@@ -42,6 +42,7 @@
   <ItemGroup>
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="TestScrollable.cs" />
+    <Compile Include="ViewModels\EditorViewModel.cs" />
     <Compile Include="ViewModels\MainWindowViewModel.cs" />
     <Compile Include="ViewModels\TestItem.cs" />
     <Compile Include="ViewModels\TestNode.cs" />
diff --git a/src/Markup/Perspex.Markup.Xaml/Context/PerspexNamespaceRegistry.cs b/src/Markup/Perspex.Markup.Xaml/Context/PerspexNamespaceRegistry.cs
index 4db1a89e7c..5efc4b2fa0 100644
--- a/src/Markup/Perspex.Markup.Xaml/Context/PerspexNamespaceRegistry.cs
+++ b/src/Markup/Perspex.Markup.Xaml/Context/PerspexNamespaceRegistry.cs
@@ -5,7 +5,6 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
-using Glass;
 using OmniXaml.Builder;
 using OmniXaml.Typing;
 using Perspex.Controls;
@@ -14,6 +13,7 @@ using Perspex.Media;
 using Perspex.Metadata;
 using Perspex.Platform;
 using Perspex.Styling;
+using Glass.Core;
 
 namespace Perspex.Markup.Xaml.Context
 {
diff --git a/src/Markup/Perspex.Markup.Xaml/Context/PerspexObjectAssembler.cs b/src/Markup/Perspex.Markup.Xaml/Context/PerspexObjectAssembler.cs
index d8f40b3fe4..7e4320be93 100644
--- a/src/Markup/Perspex.Markup.Xaml/Context/PerspexObjectAssembler.cs
+++ b/src/Markup/Perspex.Markup.Xaml/Context/PerspexObjectAssembler.cs
@@ -7,6 +7,8 @@ using OmniXaml.ObjectAssembler;
 using OmniXaml.ObjectAssembler.Commands;
 using OmniXaml.TypeConversion;
 using Perspex.Markup.Xaml.Templates;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
 
 namespace Perspex.Markup.Xaml.Context
 {
@@ -27,7 +29,8 @@ namespace Perspex.Markup.Xaml.Context
             mapping.Map<TreeDataTemplate>(x => x.Content, new TemplateLoader());
             mapping.Map<ItemsPanelTemplate>(x => x.Content, new TemplateLoader());
 
-            var valueContext = new ValueContext(typeSource, topDownValueContext);
+            var parsingDictionary = GetDictionary(settings);
+            var valueContext = new ValueContext(typeSource, topDownValueContext, parsingDictionary);
             assembler = new ObjectAssembler(typeSource, valueContext, settings);
             objectAssembler = new TemplateHostingObjectAssembler(assembler, mapping);
         }
@@ -55,5 +58,21 @@ namespace Perspex.Markup.Xaml.Context
         {
             objectAssembler.OverrideInstance(instance);
         }
+
+        private static IReadOnlyDictionary<string, object> GetDictionary(Settings settings)
+        {
+            IReadOnlyDictionary<string, object> dict;
+
+            if (settings != null)
+            {
+                dict = settings.ParsingContext;
+            }
+            else
+            {
+                dict = new ReadOnlyDictionary<string, object>(new Dictionary<string, object>());
+            }
+
+            return dict;
+        }
     }
 }
\ No newline at end of file
diff --git a/src/Markup/Perspex.Markup.Xaml/Context/PerspexTypeFeatureProvider.cs b/src/Markup/Perspex.Markup.Xaml/Context/PerspexTypeFeatureProvider.cs
index 4f3d29929c..66e1d810f5 100644
--- a/src/Markup/Perspex.Markup.Xaml/Context/PerspexTypeFeatureProvider.cs
+++ b/src/Markup/Perspex.Markup.Xaml/Context/PerspexTypeFeatureProvider.cs
@@ -165,6 +165,7 @@ namespace Perspex.Markup.Xaml.Context
             RegisterTypeConverter(typeof(RelativePoint), new RelativePointTypeConverter());
             RegisterTypeConverter(typeof(RelativeRect), new RelativeRectTypeConverter());
             RegisterTypeConverter(typeof(RowDefinitions), new RowDefinitionsTypeConverter());
+            RegisterTypeConverter(typeof(Size), new SizeTypeConverter());
             RegisterTypeConverter(typeof(Selector), new SelectorTypeConverter());
             RegisterTypeConverter(typeof(SolidColorBrush), new BrushTypeConverter());
             RegisterTypeConverter(typeof(Thickness), new ThicknessTypeConverter());
diff --git a/src/Markup/Perspex.Markup.Xaml/Context/PerspexTypeRepository.cs b/src/Markup/Perspex.Markup.Xaml/Context/PerspexTypeRepository.cs
index 4fa8c4b281..4bcb7a20a6 100644
--- a/src/Markup/Perspex.Markup.Xaml/Context/PerspexTypeRepository.cs
+++ b/src/Markup/Perspex.Markup.Xaml/Context/PerspexTypeRepository.cs
@@ -2,10 +2,9 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
-using Glass;
 using OmniXaml;
 using OmniXaml.Typing;
-using Perspex.Markup.Xaml.Data;
+using Glass.Core;
 
 namespace Perspex.Markup.Xaml.Context
 {
diff --git a/src/Markup/Perspex.Markup.Xaml/Converters/BitmapTypeConverter.cs b/src/Markup/Perspex.Markup.Xaml/Converters/BitmapTypeConverter.cs
index 3f908aa2ce..9fb58c2a73 100644
--- a/src/Markup/Perspex.Markup.Xaml/Converters/BitmapTypeConverter.cs
+++ b/src/Markup/Perspex.Markup.Xaml/Converters/BitmapTypeConverter.cs
@@ -24,6 +24,7 @@ namespace Perspex.Markup.Xaml.Converters
         public object ConvertFrom(IValueContext context, CultureInfo culture, object value)
         {
             var uri = new Uri((string)value, UriKind.RelativeOrAbsolute);
+            var baseUri = GetBaseUri(context);
             var scheme = uri.IsAbsoluteUri ? uri.Scheme : "file";
 
             switch (scheme)
@@ -32,7 +33,7 @@ namespace Perspex.Markup.Xaml.Converters
                     return new Bitmap((string)value);
                 default:
                     var assets = PerspexLocator.Current.GetService<IAssetLoader>();
-                    return new Bitmap(assets.Open(uri));
+                    return new Bitmap(assets.Open(uri, baseUri));
             }
         }
 
@@ -40,5 +41,12 @@ namespace Perspex.Markup.Xaml.Converters
         {
             throw new NotImplementedException();
         }
+
+        private Uri GetBaseUri(IValueContext context)
+        {
+            object result;
+            context.ParsingDictionary.TryGetValue("Uri", out result);
+            return result as Uri;
+        }
     }
 }
\ No newline at end of file
diff --git a/src/Markup/Perspex.Markup.Xaml/Converters/SizeTypeConverter.cs b/src/Markup/Perspex.Markup.Xaml/Converters/SizeTypeConverter.cs
new file mode 100644
index 0000000000..ec6763c555
--- /dev/null
+++ b/src/Markup/Perspex.Markup.Xaml/Converters/SizeTypeConverter.cs
@@ -0,0 +1,32 @@
+// Copyright (c) The Perspex 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.Globalization;
+using OmniXaml.TypeConversion;
+
+namespace Perspex.Markup.Xaml.Converters
+{
+    public class SizeTypeConverter : ITypeConverter
+    {
+        public bool CanConvertFrom(IValueContext context, Type sourceType)
+        {
+            return sourceType == typeof(string);
+        }
+
+        public bool CanConvertTo(IValueContext context, Type destinationType)
+        {
+            return false;
+        }
+
+        public object ConvertFrom(IValueContext context, CultureInfo culture, object value)
+        {
+            return Size.Parse((string)value, culture);
+        }
+
+        public object ConvertTo(IValueContext context, CultureInfo culture, object value, Type destinationType)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Markup/Perspex.Markup.Xaml/MarkupExtensions/StaticExtension.cs b/src/Markup/Perspex.Markup.Xaml/MarkupExtensions/StaticExtension.cs
index 11b0296d1e..7c89dd1e0d 100644
--- a/src/Markup/Perspex.Markup.Xaml/MarkupExtensions/StaticExtension.cs
+++ b/src/Markup/Perspex.Markup.Xaml/MarkupExtensions/StaticExtension.cs
@@ -4,8 +4,8 @@
 using System;
 using System.Linq;
 using System.Reflection;
-using Glass;
 using OmniXaml;
+using Glass.Core;
 
 namespace Perspex.Markup.Xaml.MarkupExtensions
 {
@@ -24,7 +24,7 @@ namespace Perspex.Markup.Xaml.MarkupExtensions
 
         public override object ProvideValue(MarkupExtensionContext markupExtensionContext)
         {
-            var typeRepository = markupExtensionContext.TypeRepository;
+            var typeRepository = markupExtensionContext.ValueContext.TypeRepository;
             var typeAndMember = GetTypeAndMember(Identifier);
             var prefixAndType = GetPrefixAndType(typeAndMember.Item1);
             var xamlType = typeRepository.GetByPrefix(prefixAndType.Item1, prefixAndType.Item2);
diff --git a/src/Markup/Perspex.Markup.Xaml/MarkupExtensions/TypeExtension.cs b/src/Markup/Perspex.Markup.Xaml/MarkupExtensions/TypeExtension.cs
index 83d951fece..b82f8eb998 100644
--- a/src/Markup/Perspex.Markup.Xaml/MarkupExtensions/TypeExtension.cs
+++ b/src/Markup/Perspex.Markup.Xaml/MarkupExtensions/TypeExtension.cs
@@ -2,10 +2,10 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
-using Glass;
 using OmniXaml;
 using OmniXaml.Attributes;
 using OmniXaml.Typing;
+using Glass.Core;
 
 namespace Perspex.Markup.Xaml.MarkupExtensions
 {
@@ -43,7 +43,7 @@ namespace Perspex.Markup.Xaml.MarkupExtensions
                 return Type;
             }
 
-            return ResolveFromString(TypeName, markupExtensionContext.TypeRepository);
+            return ResolveFromString(TypeName, markupExtensionContext.ValueContext.TypeRepository);
         }
     }
 }
\ No newline at end of file
diff --git a/src/Markup/Perspex.Markup.Xaml/OmniXAML b/src/Markup/Perspex.Markup.Xaml/OmniXAML
index 75e0dc32fe..b122549406 160000
--- a/src/Markup/Perspex.Markup.Xaml/OmniXAML
+++ b/src/Markup/Perspex.Markup.Xaml/OmniXAML
@@ -1 +1 @@
-Subproject commit 75e0dc32fe9a6d97f5b59d2b7d689db2475f444f
+Subproject commit b122549406107170bbe6e67c0d6a1a4252beef77
diff --git a/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj b/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj
index 0c003e4f75..9b72487a60 100644
--- a/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj
+++ b/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj
@@ -66,6 +66,7 @@
     <Compile Include="Converters\PerspexListTypeConverter.cs" />
     <Compile Include="Converters\PerspexPropertyTypeConverter.cs" />
     <Compile Include="Converters\PointsListTypeConverter.cs" />
+    <Compile Include="Converters\SizeTypeConverter.cs" />
     <Compile Include="Converters\PointTypeConverter.cs" />
     <Compile Include="Converters\RelativePointTypeConverter.cs" />
     <Compile Include="Converters\RelativeRectTypeConverter.cs" />
@@ -81,22 +82,22 @@
     <Compile Include="Data\SourceBindingEndpoint.cs" />
     <Compile Include="Data\StyleResourceBinding.cs" />
     <Compile Include="Data\TargetBindingEndpoint.cs" />
+    <Compile Include="glass\Glass.Core\AutoKeyDictionary.cs" />
+    <Compile Include="glass\Glass.Core\DependencySorter.cs" />
+    <Compile Include="glass\Glass.Core\EnumExtensions.cs" />
+    <Compile Include="glass\Glass.Core\Extensions.cs" />
+    <Compile Include="glass\Glass.Core\Guard.cs" />
+    <Compile Include="glass\Glass.Core\IAdd.cs" />
+    <Compile Include="glass\Glass.Core\IDependency.cs" />
+    <Compile Include="glass\Glass.Core\ReflectionExtensions.cs" />
+    <Compile Include="glass\Glass.Core\StackingLinkedList.cs" />
+    <Compile Include="glass\Glass.Core\StackingLinkedListMixin.cs" />
     <Compile Include="MarkupExtensions\StyleResourceExtension.cs" />
     <Compile Include="MarkupExtensions\BindingExtension.cs" />
     <Compile Include="MarkupExtensions\RelativeSourceExtension.cs" />
     <Compile Include="MarkupExtensions\StaticExtension.cs" />
     <Compile Include="MarkupExtensions\TemplateBindingExtension.cs" />
     <Compile Include="MarkupExtensions\TypeExtension.cs" />
-    <Compile Include="OmniXAML\Source\Glass\AutoKeyDictionary.cs" />
-    <Compile Include="OmniXAML\Source\Glass\DependencySorter.cs" />
-    <Compile Include="OmniXAML\Source\Glass\EnumExtensions.cs" />
-    <Compile Include="OmniXAML\Source\Glass\Extensions.cs" />
-    <Compile Include="OmniXAML\Source\Glass\Guard.cs" />
-    <Compile Include="OmniXAML\Source\Glass\IAdd.cs" />
-    <Compile Include="OmniXAML\Source\Glass\IDependency.cs" />
-    <Compile Include="OmniXAML\Source\Glass\ReflectionExtensions.cs" />
-    <Compile Include="OmniXAML\Source\Glass\StackingLinkedList.cs" />
-    <Compile Include="OmniXAML\Source\Glass\StackingLinkedListMixin.cs" />
     <Compile Include="OmniXAML\Source\OmniXaml\Attributes\ContentPropertyAttribute.cs" />
     <Compile Include="OmniXAML\Source\OmniXaml\Attributes\DependsOnAttribute.cs" />
     <Compile Include="OmniXAML\Source\OmniXaml\Attributes\XmlnsDefinitionAttribute.cs" />
@@ -275,6 +276,7 @@
   </ItemGroup>
   <ItemGroup>
     <None Include="app.config" />
+    <None Include="glass\Glass.Core\Glass.Core.nuspec" />
     <None Include="packages.config" />
   </ItemGroup>
   <ItemGroup>
@@ -333,6 +335,9 @@
       <HintPath>..\..\..\packages\Rx-PlatformServices.2.2.5\lib\portable-windows8+net45+wp8\System.Reactive.PlatformServices.dll</HintPath>
     </Reference>
   </ItemGroup>
+  <ItemGroup>
+    <Content Include="glass\Glass.Core\Glass.Core.csproj" />
+  </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath32)\Microsoft\Portable\$(TargetFrameworkVersion)\Microsoft.Portable.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
diff --git a/src/Markup/Perspex.Markup.Xaml/PerspexXamlLoader.cs b/src/Markup/Perspex.Markup.Xaml/PerspexXamlLoader.cs
index 68ae90d60f..c1216b16a9 100644
--- a/src/Markup/Perspex.Markup.Xaml/PerspexXamlLoader.cs
+++ b/src/Markup/Perspex.Markup.Xaml/PerspexXamlLoader.cs
@@ -15,7 +15,7 @@ namespace Perspex.Markup.Xaml
     using Controls;
     using Data;
     using OmniXaml.ObjectAssembler;
-
+    using System.Linq;
     /// <summary>
     /// Loads XAML for a perspex application.
     /// </summary>
@@ -23,6 +23,7 @@ namespace Perspex.Markup.Xaml
     {
         private static PerspexParserFactory s_parserFactory;
         private static IInstanceLifeCycleListener s_lifeCycleListener = new PerspexLifeCycleListener();
+        private static Stack<Uri> s_uriStack = new Stack<Uri>();
 
         /// <summary>
         /// Initializes a new instance of the <see cref="PerspexXamlLoader"/> class.
@@ -41,6 +42,18 @@ namespace Perspex.Markup.Xaml
         {
         }
 
+        /// <summary>
+        /// Gets the URI of the XAML file currently being loaded.
+        /// </summary>
+        /// <remarks>
+        /// TODO: Making this internal for now as I'm not sure that this is the correct
+        /// thing to do, but its needd by <see cref="StyleInclude"/> to get the URL of
+        /// the currently loading XAML file, as we can't use the OmniXAML parsing context
+        /// there. Maybe we need a way to inject OmniXAML context into the objects its
+        /// constructing?
+        /// </remarks>
+        internal static Uri UriContext => s_uriStack.Count > 0 ? s_uriStack.Peek() : null;
+
         /// <summary>
         /// Loads the XAML into a Perspex component.
         /// </summary>
@@ -84,7 +97,7 @@ namespace Perspex.Markup.Xaml
                     {
                         var initialize = rootInstance as ISupportInitialize;
                         initialize?.BeginInit();
-                        return Load(stream, rootInstance);
+                        return Load(stream, rootInstance, uri);
                     }
                 }
             }
@@ -96,11 +109,14 @@ namespace Perspex.Markup.Xaml
         /// Loads XAML from a URI.
         /// </summary>
         /// <param name="uri">The URI of the XAML file.</param>
+        /// <param name="baseUri">
+        /// A base URI to use if <paramref name="uri"/> is relative.
+        /// </param>
         /// <param name="rootInstance">
         /// The optional instance into which the XAML should be loaded.
         /// </param>
         /// <returns>The loaded object.</returns>
-        public object Load(Uri uri, object rootInstance = null)
+        public object Load(Uri uri, Uri baseUri = null, object rootInstance = null)
         {
             Contract.Requires<ArgumentNullException>(uri != null);
 
@@ -112,9 +128,9 @@ namespace Perspex.Markup.Xaml
                     "Could not create IAssetLoader : maybe Application.RegisterServices() wasn't called?");
             }
 
-            using (var stream = assetLocator.Open(uri))
+            using (var stream = assetLocator.Open(uri, baseUri))
             {
-                return Load(stream, rootInstance);
+                return Load(stream, rootInstance, uri);
             }
         }
 
@@ -143,23 +159,43 @@ namespace Perspex.Markup.Xaml
         /// <param name="rootInstance">
         /// The optional instance into which the XAML should be loaded.
         /// </param>
+        /// <param name="uri">The URI of the XAML</param>
         /// <returns>The loaded object.</returns>
-        public object Load(Stream stream, object rootInstance = null)
+        public object Load(Stream stream, object rootInstance = null, Uri uri = null)
         {
-            var result = base.Load(stream, new Settings
+            try
             {
-                RootInstance = rootInstance,
-                InstanceLifeCycleListener = s_lifeCycleListener,
-            });
+                if (uri != null)
+                {
+                    s_uriStack.Push(uri);
+                }
 
-            var topLevel = result as TopLevel;
+                var result = base.Load(stream, new Settings
+                {
+                    RootInstance = rootInstance,
+                    InstanceLifeCycleListener = s_lifeCycleListener,
+                    ParsingContext = new Dictionary<string, object>
+                    {
+                        { "Uri", uri }
+                    }
+                });
+
+                var topLevel = result as TopLevel;
+
+                if (topLevel != null)
+                {
+                    DelayedBinding.ApplyBindings(topLevel);
+                }
 
-            if (topLevel != null)
+                return result;
+            }
+            finally
             {
-                DelayedBinding.ApplyBindings(topLevel);
+                if (uri != null)
+                {
+                    s_uriStack.Pop();
+                }
             }
-
-            return result;
         }
 
         private static PerspexParserFactory GetParserFactory()
diff --git a/src/Markup/Perspex.Markup.Xaml/Styling/StyleInclude.cs b/src/Markup/Perspex.Markup.Xaml/Styling/StyleInclude.cs
index 6e74271f58..08641e0dfe 100644
--- a/src/Markup/Perspex.Markup.Xaml/Styling/StyleInclude.cs
+++ b/src/Markup/Perspex.Markup.Xaml/Styling/StyleInclude.cs
@@ -11,8 +11,20 @@ namespace Perspex.Markup.Xaml.Styling
     /// </summary>
     public class StyleInclude : IStyle
     {
+        private Uri _baseUri;
         private IStyle _loaded;
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="StyleInclude"/> class.
+        /// </summary>
+        public StyleInclude()
+        {
+            // StyleInclude will usually be loaded from XAML and its URI can be relative to the
+            // XAML file that its included in, so store the current XAML file's URI if any as
+            // a base URI.
+            _baseUri = PerspexXamlLoader.UriContext;
+        }
+
         /// <summary>
         /// Gets or sets the source URL.
         /// </summary>
@@ -28,7 +40,7 @@ namespace Perspex.Markup.Xaml.Styling
                 if (_loaded == null)
                 {
                     var loader = new PerspexXamlLoader();
-                    _loaded = (IStyle)loader.Load(Source);
+                    _loaded = (IStyle)loader.Load(Source, _baseUri);
                 }
 
                 return _loaded;
diff --git a/src/Markup/Perspex.Markup.Xaml/glass b/src/Markup/Perspex.Markup.Xaml/glass
new file mode 160000
index 0000000000..9e17adbd3a
--- /dev/null
+++ b/src/Markup/Perspex.Markup.Xaml/glass
@@ -0,0 +1 @@
+Subproject commit 9e17adbd3ac0b342e7922ee2d5a11e5d50b7e687
diff --git a/src/Perspex.Base/PerspexObject.cs b/src/Perspex.Base/PerspexObject.cs
index 4cd6998b76..81640237e8 100644
--- a/src/Perspex.Base/PerspexObject.cs
+++ b/src/Perspex.Base/PerspexObject.cs
@@ -23,17 +23,6 @@ namespace Perspex
     /// </remarks>
     public class PerspexObject : IPerspexObject, IPerspexObjectDebug, INotifyPropertyChanged, IPriorityValueOwner
     {
-        /// <summary>
-        /// Maintains a list of direct property binding subscriptions so that the binding source
-        /// doesn't get collected.
-        /// </summary>
-        /// <remarks>
-        /// If/when we provide a ClearBindings() method, then this collection will be need to be
-        /// moved to an instance field and indexed by property, but until that point a static
-        /// collection will suffice.
-        /// </remarks>
-        private static List<IDisposable> s_directBindings = new List<IDisposable>();
-
         /// <summary>
         /// The parent object that inherited values are inherited from.
         /// </summary>
@@ -45,6 +34,12 @@ namespace Perspex
         private readonly Dictionary<PerspexProperty, PriorityValue> _values =
             new Dictionary<PerspexProperty, PriorityValue>();
 
+        /// <summary>
+        /// Maintains a list of direct property binding subscriptions so that the binding source
+        /// doesn't get collected.
+        /// </summary>
+        private List<IDisposable> _directBindings;
+
         /// <summary>
         /// Event handler for <see cref="INotifyPropertyChanged"/> implementation.
         /// </summary>
@@ -403,22 +398,27 @@ namespace Perspex
                 IDisposable subscription = null;
                 IDisposable validationSubcription = null;
 
+                if (_directBindings == null)
+                {
+                    _directBindings = new List<IDisposable>();
+                }
+
                 subscription = source
                     .Where(x =>  !(x is ValidationStatus))
                     .Select(x => CastOrDefault(x, property.PropertyType))
-                    .Do(_ => { }, () => s_directBindings.Remove(subscription))
+                    .Do(_ => { }, () => _directBindings.Remove(subscription))
                     .Subscribe(x => DirectBindingSet(property, x));
                 validationSubcription = source
                     .OfType<ValidationStatus>()
                     .Subscribe(x => DataValidation(property, x));
 
-                s_directBindings.Add(subscription);
+                _directBindings.Add(subscription);
 
                 return Disposable.Create(() =>
                 {
                     validationSubcription.Dispose();
                     subscription.Dispose();
-                    s_directBindings.Remove(subscription);
+                    _directBindings.Remove(subscription);
                 });
             }
             else
diff --git a/src/Perspex.Base/Platform/IAssetLoader.cs b/src/Perspex.Base/Platform/IAssetLoader.cs
index 00f9d7e4d3..cd32d7bd3d 100644
--- a/src/Perspex.Base/Platform/IAssetLoader.cs
+++ b/src/Perspex.Base/Platform/IAssetLoader.cs
@@ -21,22 +21,27 @@ namespace Perspex.Platform
         /// <param name="asm"></param>
         void SetDefaultAssembly(Assembly asm);
 
-
         /// <summary>
         /// Checks if an asset with the specified URI exists.
         /// </summary>
         /// <param name="uri">The URI.</param>
+        /// <param name="baseUri">
+        /// A base URI to use if <paramref name="uri"/> is relative.
+        /// </param>
         /// <returns>True if the asset could be found; otherwise false.</returns>
-        bool Exists(Uri uri);
+        bool Exists(Uri uri, Uri baseUri = null);
 
         /// <summary>
         /// Opens the resource with the requested URI.
         /// </summary>
         /// <param name="uri">The URI.</param>
+        /// <param name="baseUri">
+        /// A base URI to use if <paramref name="uri"/> is relative.
+        /// </param>
         /// <returns>A stream containing the resource contents.</returns>
         /// <exception cref="FileNotFoundException">
         /// The resource was not found.
         /// </exception>
-        Stream Open(Uri uri);
+        Stream Open(Uri uri, Uri baseUri = null);
     }
 }
diff --git a/src/Perspex.Controls/Generators/ItemContainerGenerator.cs b/src/Perspex.Controls/Generators/ItemContainerGenerator.cs
index a162ce08de..c945d7b5bf 100644
--- a/src/Perspex.Controls/Generators/ItemContainerGenerator.cs
+++ b/src/Perspex.Controls/Generators/ItemContainerGenerator.cs
@@ -94,9 +94,15 @@ namespace Perspex.Controls.Generators
         /// <inheritdoc/>
         public virtual IEnumerable<ItemContainer> RemoveRange(int startingIndex, int count)
         {
-            var result = _containers.GetRange(startingIndex, count);
-            _containers.RemoveRange(startingIndex, count);
-            Dematerialized?.Invoke(this, new ItemContainerEventArgs(startingIndex, result));
+            List<ItemContainer> result = new List<ItemContainer>();
+
+            if (startingIndex < _containers.Count)
+            {
+                result.AddRange(_containers.GetRange(startingIndex, count));
+                _containers.RemoveRange(startingIndex, count);
+                Dematerialized?.Invoke(this, new ItemContainerEventArgs(startingIndex, result));
+            }
+
             return result;
         }
 
diff --git a/src/Perspex.Controls/Presenters/CarouselPresenter.cs b/src/Perspex.Controls/Presenters/CarouselPresenter.cs
index 1a7de96a16..6776c3a3bc 100644
--- a/src/Perspex.Controls/Presenters/CarouselPresenter.cs
+++ b/src/Perspex.Controls/Presenters/CarouselPresenter.cs
@@ -6,6 +6,7 @@ using System.Linq;
 using System.Reactive.Linq;
 using System.Threading.Tasks;
 using Perspex.Animation;
+using Perspex.Controls.Generators;
 using Perspex.Controls.Primitives;
 using Perspex.Controls.Utils;
 using Perspex.Data;
@@ -103,7 +104,19 @@ namespace Perspex.Controls.Presenters
         /// <inheritdoc/>
         protected override void ItemsChanged(NotifyCollectionChangedEventArgs e)
         {
-            // TODO: Handle items changing.
+            // TODO: Handle items changing.           
+            switch (e.Action)
+            {
+                case NotifyCollectionChangedAction.Remove:
+                    if (!IsVirtualized)
+                    {
+                        var generator = ItemContainerGenerator;
+                        var containers = generator.RemoveRange(e.OldStartingIndex, e.OldItems.Count);
+                        Panel.Children.RemoveAll(containers.Select(x => x.ContainerControl));
+                    }
+                    break;
+
+            }
         }
 
         /// <summary>
diff --git a/src/Perspex.Controls/Primitives/SelectingItemsControl.cs b/src/Perspex.Controls/Primitives/SelectingItemsControl.cs
index 629dbd8d6f..e683fc43f9 100644
--- a/src/Perspex.Controls/Primitives/SelectingItemsControl.cs
+++ b/src/Perspex.Controls/Primitives/SelectingItemsControl.cs
@@ -377,6 +377,23 @@ namespace Perspex.Controls.Primitives
             }
         }
 
+        /// <inheritdoc/>
+        protected override void OnContainersDematerialized(ItemContainerEventArgs e)
+        {
+            base.OnContainersDematerialized(e);
+
+            var panel = (InputElement)Presenter.Panel;
+
+            foreach (var container in e.Containers)
+            {
+                if (KeyboardNavigation.GetTabOnceActiveElement(panel) == container.ContainerControl)
+                {
+                    KeyboardNavigation.SetTabOnceActiveElement(panel, null);
+                    break;
+                }
+            }
+        }
+
         /// <inheritdoc/>
         protected override void OnDataContextChanging()
         {
diff --git a/src/Perspex.Controls/Primitives/ToggleButton.cs b/src/Perspex.Controls/Primitives/ToggleButton.cs
index 30b76aea1c..3f6499137d 100644
--- a/src/Perspex.Controls/Primitives/ToggleButton.cs
+++ b/src/Perspex.Controls/Primitives/ToggleButton.cs
@@ -32,6 +32,7 @@ namespace Perspex.Controls.Primitives
         protected override void OnClick(RoutedEventArgs e)
         {
             Toggle();
+            base.OnClick(e);
         }
 
         protected virtual void Toggle()
diff --git a/src/Perspex.Input/FocusManager.cs b/src/Perspex.Input/FocusManager.cs
index 1ce645fd13..78935dc13e 100644
--- a/src/Perspex.Input/FocusManager.cs
+++ b/src/Perspex.Input/FocusManager.cs
@@ -39,7 +39,7 @@ namespace Perspex.Input
         /// <summary>
         /// Gets the currently focused <see cref="IInputElement"/>.
         /// </summary>
-        public IInputElement Current => KeyboardDevice.Instance.FocusedElement;
+        public IInputElement Current => KeyboardDevice.Instance?.FocusedElement;
 
         /// <summary>
         /// Gets the current focus scope.
@@ -82,9 +82,12 @@ namespace Perspex.Input
                     if (_focusScopes.TryGetValue(scope, out element))
                     {
                         Focus(element, method);
-                        break;
+                        return;
                     }
                 }
+
+                // Couldn't find a focus scope, clear focus.
+                SetFocusedElement(Scope, null);
             }
         }
 
@@ -111,7 +114,7 @@ namespace Perspex.Input
 
             if (Scope == scope)
             {
-                KeyboardDevice.Instance.SetFocusedElement(element, method, modifiers);
+                KeyboardDevice.Instance?.SetFocusedElement(element, method, modifiers);
             }
         }
 
@@ -176,7 +179,7 @@ namespace Perspex.Input
             if (sender == e.Source)
             {
                 var ev = (PointerPressedEventArgs)e;
-                var element = (ev.Device.Captured as IInputElement) ?? (e.Source as IInputElement);
+                var element = (ev.Device?.Captured as IInputElement) ?? (e.Source as IInputElement);
 
                 if (element == null || !CanFocus(element))
                 {
diff --git a/src/Perspex.Input/Gestures.cs b/src/Perspex.Input/Gestures.cs
index 48e9d87f86..fb68cc5d69 100644
--- a/src/Perspex.Input/Gestures.cs
+++ b/src/Perspex.Input/Gestures.cs
@@ -18,7 +18,7 @@ namespace Perspex.Input
             RoutingStrategies.Bubble,
             typeof(Gestures));
 
-        private static IInteractive s_lastPress;
+        private static WeakReference s_lastPress;
 
         static Gestures()
         {
@@ -34,9 +34,9 @@ namespace Perspex.Input
 
                 if (e.ClickCount <= 1)
                 {
-                    s_lastPress = e.Source;
+                    s_lastPress = new WeakReference(e.Source);
                 }
-                else if (e.ClickCount == 2 && s_lastPress == e.Source)
+                else if (s_lastPress?.IsAlive == true && e.ClickCount == 2 && s_lastPress.Target == e.Source)
                 {
                     e.Source.RaiseEvent(new RoutedEventArgs(DoubleTappedEvent));
                 }
@@ -49,9 +49,9 @@ namespace Perspex.Input
             {
                 var e = (PointerReleasedEventArgs)ev;
 
-                if (s_lastPress == e.Source)
+                if (s_lastPress?.IsAlive == true && s_lastPress.Target == e.Source)
                 {
-                    s_lastPress.RaiseEvent(new RoutedEventArgs(TappedEvent));
+                    ((IInteractive)s_lastPress.Target).RaiseEvent(new RoutedEventArgs(TappedEvent));
                 }
             }
         }
diff --git a/src/Perspex.Input/InputElement.cs b/src/Perspex.Input/InputElement.cs
index 00e53df646..8c976bb155 100644
--- a/src/Perspex.Input/InputElement.cs
+++ b/src/Perspex.Input/InputElement.cs
@@ -376,9 +376,9 @@ namespace Perspex.Input
         }
 
         /// <inheritdoc/>
-        protected override void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
+        protected override void OnDetachedFromVisualTreeCore(VisualTreeAttachmentEventArgs e)
         {
-            base.OnDetachedFromVisualTree(e);
+            base.OnDetachedFromVisualTreeCore(e);
 
             if (IsFocused)
             {
@@ -387,9 +387,9 @@ namespace Perspex.Input
         }
 
         /// <inheritdoc/>
-        protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
+        protected override void OnAttachedToVisualTreeCore(VisualTreeAttachmentEventArgs e)
         {
-            base.OnAttachedToVisualTree(e);
+            base.OnAttachedToVisualTreeCore(e);
             UpdateIsEnabledCore();
         }
 
diff --git a/src/Perspex.SceneGraph/Media/ArcSegment.cs b/src/Perspex.SceneGraph/Media/ArcSegment.cs
new file mode 100644
index 0000000000..35a1bb87c1
--- /dev/null
+++ b/src/Perspex.SceneGraph/Media/ArcSegment.cs
@@ -0,0 +1,103 @@
+// Copyright (c) The Perspex Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+namespace Perspex.Media
+{
+    public sealed class ArcSegment : PathSegment
+    {
+        /// <summary>
+        /// Defines the <see cref="IsLargeArc"/> property.
+        /// </summary>
+        public static readonly StyledProperty<bool> IsLargeArcProperty
+                     = PerspexProperty.Register<ArcSegment, bool>(nameof(IsLargeArc), false);
+
+        /// <summary>
+        /// Defines the <see cref="Point"/> property.
+        /// </summary>
+        public static readonly StyledProperty<Point> PointProperty
+                                = PerspexProperty.Register<ArcSegment, Point>(nameof(Point));
+
+        /// <summary>
+        /// Defines the <see cref="RotationAngle"/> property.
+        /// </summary>
+        public static readonly StyledProperty<double> RotationAngleProperty
+                                     = PerspexProperty.Register<ArcSegment, double>(nameof(RotationAngle), 0);
+
+        /// <summary>
+        /// Defines the <see cref="Size"/> property.
+        /// </summary>
+        public static readonly StyledProperty<Size> SizeProperty
+                    = PerspexProperty.Register<ArcSegment, Size>(nameof(Size));
+
+        /// <summary>
+        /// Defines the <see cref="SweepDirection"/> property.
+        /// </summary>
+        public static readonly StyledProperty<SweepDirection> SweepDirectionProperty
+                = PerspexProperty.Register<ArcSegment, SweepDirection>(nameof(SweepDirection), SweepDirection.Clockwise);
+
+        /// <summary>
+        /// Gets or sets a value indicating whether this instance is large arc.
+        /// </summary>
+        /// <value>
+        /// <c>true</c> if this instance is large arc; otherwise, <c>false</c>.
+        /// </value>
+        public bool IsLargeArc
+        {
+            get { return GetValue(IsLargeArcProperty); }
+            set { SetValue(IsLargeArcProperty, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the point.
+        /// </summary>
+        /// <value>
+        /// The point.
+        /// </value>
+        public Point Point
+        {
+            get { return GetValue(PointProperty); }
+            set { SetValue(PointProperty, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the rotation angle.
+        /// </summary>
+        /// <value>
+        /// The rotation angle.
+        /// </value>
+        public double RotationAngle
+        {
+            get { return GetValue(RotationAngleProperty); }
+            set { SetValue(RotationAngleProperty, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the size.
+        /// </summary>
+        /// <value>
+        /// The size.
+        /// </value>
+        public Size Size
+        {
+            get { return GetValue(SizeProperty); }
+            set { SetValue(SizeProperty, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the sweep direction.
+        /// </summary>
+        /// <value>
+        /// The sweep direction.
+        /// </value>
+        public SweepDirection SweepDirection
+        {
+            get { return GetValue(SweepDirectionProperty); }
+            set { SetValue(SweepDirectionProperty, value); }
+        }
+
+        protected internal override void ApplyTo(StreamGeometryContext ctx)
+        {
+            ctx.ArcTo(Point, Size, RotationAngle, IsLargeArc, SweepDirection);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Perspex.SceneGraph/Media/BezierSegment .cs b/src/Perspex.SceneGraph/Media/BezierSegment .cs
new file mode 100644
index 0000000000..7a7ad9827a
--- /dev/null
+++ b/src/Perspex.SceneGraph/Media/BezierSegment .cs	
@@ -0,0 +1,65 @@
+// Copyright (c) The Perspex Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+namespace Perspex.Media
+{
+    public sealed class BezierSegment : PathSegment
+    {
+        /// <summary>
+        /// Defines the <see cref="Point1"/> property.
+        /// </summary>
+        public static readonly StyledProperty<Point> Point1Property
+                        = PerspexProperty.Register<BezierSegment, Point>(nameof(Point1));
+        /// <summary>
+        /// Defines the <see cref="Point2"/> property.
+        /// </summary>
+        public static readonly StyledProperty<Point> Point2Property
+                        = PerspexProperty.Register<BezierSegment, Point>(nameof(Point2));
+        /// <summary>
+        /// Defines the <see cref="Point3"/> property.
+        /// </summary>
+        public static readonly StyledProperty<Point> Point3Property
+                        = PerspexProperty.Register<BezierSegment, Point>(nameof(Point3));
+
+        /// <summary>
+        /// Gets or sets the point1.
+        /// </summary>
+        /// <value>
+        /// The point1.
+        /// </value>
+        public Point Point1
+        {
+            get { return GetValue(Point1Property); }
+            set { SetValue(Point1Property, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the point2.
+        /// </summary>
+        /// <value>
+        /// The point2.
+        /// </value>
+        public Point Point2
+        {
+            get { return GetValue(Point2Property); }
+            set { SetValue(Point2Property, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the point3.
+        /// </summary>
+        /// <value>
+        /// The point3.
+        /// </value>
+        public Point Point3
+        {
+            get { return GetValue(Point3Property); }
+            set { SetValue(Point3Property, value); }
+        }
+
+        protected internal override void ApplyTo(StreamGeometryContext ctx)
+        {
+            ctx.CubicBezierTo(Point1, Point2, Point3);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Perspex.SceneGraph/Media/Geometry.cs b/src/Perspex.SceneGraph/Media/Geometry.cs
index 806d5321a5..7e48169efe 100644
--- a/src/Perspex.SceneGraph/Media/Geometry.cs
+++ b/src/Perspex.SceneGraph/Media/Geometry.cs
@@ -36,7 +36,7 @@ namespace Perspex.Media
         /// <summary>
         /// Gets the platform-specific implementation of the geometry.
         /// </summary>
-        public IGeometryImpl PlatformImpl
+        public virtual IGeometryImpl PlatformImpl
         {
             get;
             protected set;
diff --git a/src/Perspex.SceneGraph/Media/LineSegment.cs b/src/Perspex.SceneGraph/Media/LineSegment.cs
new file mode 100644
index 0000000000..716697b02c
--- /dev/null
+++ b/src/Perspex.SceneGraph/Media/LineSegment.cs
@@ -0,0 +1,31 @@
+// Copyright (c) The Perspex Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+namespace Perspex.Media
+{
+    public sealed class LineSegment : PathSegment
+    {
+        /// <summary>
+        /// Defines the <see cref="Point"/> property.
+        /// </summary>
+        public static readonly StyledProperty<Point> PointProperty
+                        = PerspexProperty.Register<LineSegment, Point>(nameof(Point));
+
+        /// <summary>
+        /// Gets or sets the point.
+        /// </summary>
+        /// <value>
+        /// The point.
+        /// </value>
+        public Point Point
+        {
+            get { return GetValue(PointProperty); }
+            set { SetValue(PointProperty, value); }
+        }
+
+        protected internal override void ApplyTo(StreamGeometryContext ctx)
+        {
+            ctx.LineTo(Point);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Perspex.SceneGraph/Media/PathFigure.cs b/src/Perspex.SceneGraph/Media/PathFigure.cs
new file mode 100644
index 0000000000..8ce54d4bd8
--- /dev/null
+++ b/src/Perspex.SceneGraph/Media/PathFigure.cs
@@ -0,0 +1,102 @@
+// Copyright (c) The Perspex Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using Perspex.Metadata;
+
+namespace Perspex.Media
+{
+    public sealed class PathFigure : PerspexObject
+    {
+        /// <summary>
+        /// Defines the <see cref="IsClosed"/> property.
+        /// </summary>
+        public static readonly StyledProperty<bool> IsClosedProperty
+                            = PerspexProperty.Register<PathFigure, bool>(nameof(IsClosed), true);
+        /// <summary>
+        /// Defines the <see cref="IsFilled"/> property.
+        /// </summary>
+        public static readonly StyledProperty<bool> IsFilledProperty
+                            = PerspexProperty.Register<PathFigure, bool>(nameof(IsFilled), true);
+        /// <summary>
+        /// Defines the <see cref="Segments"/> property.
+        /// </summary>
+        public static readonly DirectProperty<PathFigure, PathSegments> SegmentsProperty
+                        = PerspexProperty.RegisterDirect<PathFigure, PathSegments>(nameof(Segments), f => f.Segments, (f, s) => f.Segments = s);
+        /// <summary>
+        /// Defines the <see cref="StartPoint"/> property.
+        /// </summary>
+        public static readonly StyledProperty<Point> StartPointProperty
+                        = PerspexProperty.Register<PathFigure, Point>(nameof(StartPoint));
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PathFigure"/> class.
+        /// </summary>
+        public PathFigure()
+        {
+            Segments = new PathSegments();
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether this instance is closed.
+        /// </summary>
+        /// <value>
+        ///   <c>true</c> if this instance is closed; otherwise, <c>false</c>.
+        /// </value>
+        public bool IsClosed
+        {
+            get { return GetValue(IsClosedProperty); }
+            set { SetValue(IsClosedProperty, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether this instance is filled.
+        /// </summary>
+        /// <value>
+        ///   <c>true</c> if this instance is filled; otherwise, <c>false</c>.
+        /// </value>
+        public bool IsFilled
+        {
+            get { return GetValue(IsFilledProperty); }
+            set { SetValue(IsFilledProperty, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the segments.
+        /// </summary>
+        /// <value>
+        /// The segments.
+        /// </value>
+        [Content]
+        public PathSegments Segments
+        {
+            get { return _segments; }
+            set { SetAndRaise(SegmentsProperty, ref _segments, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the start point.
+        /// </summary>
+        /// <value>
+        /// The start point.
+        /// </value>
+        public Point StartPoint
+        {
+            get { return GetValue(StartPointProperty); }
+            set { SetValue(StartPointProperty, value); }
+        }
+
+        internal void ApplyTo(StreamGeometryContext ctx)
+        {
+            ctx.BeginFigure(StartPoint, IsFilled);
+
+            foreach (var segment in Segments)
+            {
+                segment.ApplyTo(ctx);
+            }
+
+            ctx.EndFigure(IsClosed);
+        }
+
+        private PathSegments _segments;
+    }
+}
\ No newline at end of file
diff --git a/src/Perspex.SceneGraph/Media/PathGeometry.cs b/src/Perspex.SceneGraph/Media/PathGeometry.cs
new file mode 100644
index 0000000000..245885d4b0
--- /dev/null
+++ b/src/Perspex.SceneGraph/Media/PathGeometry.cs
@@ -0,0 +1,123 @@
+// Copyright (c) The Perspex Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using Perspex.Collections;
+using Perspex.Metadata;
+using Perspex.Platform;
+using System;
+
+namespace Perspex.Media
+{
+    public class PathGeometry : StreamGeometry
+    {
+        /// <summary>
+        /// Defines the <see cref="Figures"/> property.
+        /// </summary>
+        public static readonly DirectProperty<PathGeometry, PathFigures> FiguresProperty =
+            PerspexProperty.RegisterDirect<PathGeometry, PathFigures>(nameof(Figures), g => g.Figures, (g, f) => g.Figures = f);
+
+        /// <summary>
+        /// Defines the <see cref="FillRule"/> property.
+        /// </summary>
+        public static readonly StyledProperty<FillRule> FillRuleProperty =
+                                 PerspexProperty.Register<PathGeometry, FillRule>(nameof(FillRule));
+
+        static PathGeometry()
+        {
+            FiguresProperty.Changed.Subscribe(onNext: v =>
+            {
+                (v.Sender as PathGeometry)?.OnFiguresChanged(v.OldValue as PathFigures, v.NewValue as PathFigures);
+            });
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PathGeometry"/> class.
+        /// </summary>
+        public PathGeometry()
+        {
+            Figures = new PathFigures();
+        }
+
+        /// <summary>
+        /// Gets or sets the figures.
+        /// </summary>
+        /// <value>
+        /// The figures.
+        /// </value>
+        [Content]
+        public PathFigures Figures
+        {
+            get { return _figures; }
+            set { SetAndRaise(FiguresProperty, ref _figures, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the fill rule.
+        /// </summary>
+        /// <value>
+        /// The fill rule.
+        /// </value>
+        public FillRule FillRule
+        {
+            get { return GetValue(FillRuleProperty); }
+            set { SetValue(FillRuleProperty, value); }
+        }
+
+        public override IGeometryImpl PlatformImpl
+        {
+            get
+            {
+                PrepareIfNeeded();
+                return base.PlatformImpl;
+            }
+
+            protected set
+            {
+                base.PlatformImpl = value;
+            }
+        }
+
+        public override Geometry Clone()
+        {
+            PrepareIfNeeded();
+
+            return base.Clone();
+        }
+
+        public void PrepareIfNeeded()
+        {
+            if (_isDirty)
+            {
+                _isDirty = false;
+
+                using (var ctx = Open())
+                {
+                    ctx.SetFillRule(FillRule);
+                    foreach (var f in Figures)
+                    {
+                        f.ApplyTo(ctx);
+                    }
+                }
+            }
+        }
+
+        internal void NotifyChanged()
+        {
+            _isDirty = true;
+        }
+
+        private PathFigures _figures;
+        private IDisposable _figuresObserver = null;
+        private IDisposable _figuresPropertiesObserver = null;
+        private bool _isDirty = true;
+
+        private void OnFiguresChanged(PathFigures oldValue, PathFigures newValue)
+        {
+            _figuresObserver?.Dispose();
+            _figuresPropertiesObserver?.Dispose();
+
+            _figuresObserver = newValue?.ForEachItem(f => NotifyChanged(), f => NotifyChanged(), () => NotifyChanged());
+            _figuresPropertiesObserver = newValue?.TrackItemPropertyChanged(t => NotifyChanged());
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Perspex.SceneGraph/Media/PathGeometryCollections.cs b/src/Perspex.SceneGraph/Media/PathGeometryCollections.cs
new file mode 100644
index 0000000000..d93cedaede
--- /dev/null
+++ b/src/Perspex.SceneGraph/Media/PathGeometryCollections.cs
@@ -0,0 +1,15 @@
+// Copyright (c) The Perspex Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using Perspex.Collections;
+
+namespace Perspex.Media
+{
+    public sealed class PathFigures : PerspexList<PathFigure>
+    {
+    }
+
+    public sealed class PathSegments : PerspexList<PathSegment>
+    {
+    }
+}
\ No newline at end of file
diff --git a/src/Perspex.SceneGraph/Media/PathSegment.cs b/src/Perspex.SceneGraph/Media/PathSegment.cs
new file mode 100644
index 0000000000..523494644b
--- /dev/null
+++ b/src/Perspex.SceneGraph/Media/PathSegment.cs
@@ -0,0 +1,10 @@
+// Copyright (c) The Perspex Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+namespace Perspex.Media
+{
+    public abstract class PathSegment : PerspexObject
+    {
+        protected internal abstract void ApplyTo(StreamGeometryContext ctx);
+    }
+}
\ No newline at end of file
diff --git a/src/Perspex.SceneGraph/Media/QuadraticBezierSegment .cs b/src/Perspex.SceneGraph/Media/QuadraticBezierSegment .cs
new file mode 100644
index 0000000000..f347a8ee26
--- /dev/null
+++ b/src/Perspex.SceneGraph/Media/QuadraticBezierSegment .cs	
@@ -0,0 +1,46 @@
+namespace Perspex.Media
+{
+    public sealed class QuadraticBezierSegment : PathSegment
+    {
+        /// <summary>
+        /// Defines the <see cref="Point1"/> property.
+        /// </summary>
+        public static readonly StyledProperty<Point> Point1Property
+                        = PerspexProperty.Register<QuadraticBezierSegment, Point>(nameof(Point1));
+
+        /// <summary>
+        /// Defines the <see cref="Point2"/> property.
+        /// </summary>
+        public static readonly StyledProperty<Point> Point2Property
+                        = PerspexProperty.Register<QuadraticBezierSegment, Point>(nameof(Point2));
+
+        /// <summary>
+        /// Gets or sets the point1.
+        /// </summary>
+        /// <value>
+        /// The point1.
+        /// </value>
+        public Point Point1
+        {
+            get { return GetValue(Point1Property); }
+            set { SetValue(Point1Property, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the point2.
+        /// </summary>
+        /// <value>
+        /// The point2.
+        /// </value>
+        public Point Point2
+        {
+            get { return GetValue(Point2Property); }
+            set { SetValue(Point2Property, value); }
+        }
+
+        protected internal override void ApplyTo(StreamGeometryContext ctx)
+        {
+            ctx.QuadraticBezierTo(Point1, Point2);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Perspex.SceneGraph/Media/TransformGroup.cs b/src/Perspex.SceneGraph/Media/TransformGroup.cs
new file mode 100644
index 0000000000..79694bbfc7
--- /dev/null
+++ b/src/Perspex.SceneGraph/Media/TransformGroup.cs
@@ -0,0 +1,57 @@
+// Copyright (c) The Perspex Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using Perspex.Collections;
+using Perspex.Metadata;
+
+namespace Perspex.Media
+{
+    public class TransformGroup : Transform
+    {
+        /// <summary>
+        /// Defines the <see cref="Children"/> property.
+        /// </summary>
+        public static readonly PerspexProperty<Transforms> ChildrenProperty =
+            PerspexProperty.Register<TransformGroup, Transforms>(nameof(Children));
+
+        public TransformGroup()
+        {
+            Children = new Transforms();
+        }
+
+        /// <summary>
+        /// Gets or sets the children.
+        /// </summary>
+        /// <value>
+        /// The children.
+        /// </value>
+        [Content]
+        public Transforms Children
+        {
+            get { return GetValue(ChildrenProperty); }
+            set { SetValue(ChildrenProperty, value); }
+        }
+
+        /// <summary>
+        /// Gets the tranform's <see cref="Matrix" />.
+        /// </summary>
+        public override Matrix Value
+        {
+            get
+            {
+                Matrix result = Matrix.Identity;
+
+                foreach (var t in Children)
+                {
+                    result *= t.Value;
+                }
+
+                return result;
+            }
+        }
+    }
+
+    public sealed class Transforms : PerspexList<Transform>
+    {
+    }
+}
\ No newline at end of file
diff --git a/src/Perspex.SceneGraph/Perspex.SceneGraph.csproj b/src/Perspex.SceneGraph/Perspex.SceneGraph.csproj
index ea84ae710e..9c2867c5e9 100644
--- a/src/Perspex.SceneGraph/Perspex.SceneGraph.csproj
+++ b/src/Perspex.SceneGraph/Perspex.SceneGraph.csproj
@@ -61,11 +61,14 @@
     <Compile Include="Matrix.cs" />
     <Compile Include="Media\AlignmentY.cs" />
     <Compile Include="Media\AlignmentX.cs" />
+    <Compile Include="Media\ArcSegment.cs" />
+    <Compile Include="Media\BezierSegment .cs" />
     <Compile Include="Media\Brush.cs" />
     <Compile Include="Media\Brushes.cs" />
     <Compile Include="Media\BrushMappingMode.cs" />
     <Compile Include="Media\Color.cs" />
     <Compile Include="Media\Colors.cs" />
+    <Compile Include="Media\TransformGroup.cs" />
     <Compile Include="Media\DashStyle.cs" />
     <Compile Include="Media\DrawingContext.cs" />
     <Compile Include="Media\FillRule.cs" />
@@ -75,9 +78,15 @@
     <Compile Include="Media\IBrush.cs" />
     <Compile Include="Media\ISolidColorBrush.cs" />
     <Compile Include="Media\LineGeometry.cs" />
+    <Compile Include="Media\LineSegment.cs" />
     <Compile Include="Media\Mutable\SolidColorBrush.cs" />
+    <Compile Include="Media\PathGeometryCollections.cs" />
+    <Compile Include="Media\PathFigure.cs" />
+    <Compile Include="Media\PathGeometry.cs" />
+    <Compile Include="Media\PathSegment.cs" />
     <Compile Include="Media\PenLineJoin.cs" />
     <Compile Include="Media\PolylineGeometry.cs" />
+    <Compile Include="Media\QuadraticBezierSegment .cs" />
     <Compile Include="Media\RadialGradientBrush.cs" />
     <Compile Include="Media\LinearGradientBrush.cs" />
     <Compile Include="Media\MediaExtensions.cs" />
diff --git a/src/Perspex.SceneGraph/Size.cs b/src/Perspex.SceneGraph/Size.cs
index 1e7acc0096..648aaf6f6d 100644
--- a/src/Perspex.SceneGraph/Size.cs
+++ b/src/Perspex.SceneGraph/Size.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.Globalization;
+using System.Linq;
 
 namespace Perspex
 {
@@ -128,6 +129,28 @@ namespace Perspex
             return new Size(size._width - toSubstract._width, size._height - toSubstract._height);
         }
 
+        /// <summary>
+        /// Parses a <see cref="Size"/> string.
+        /// </summary>
+        /// <param name="s">The string.</param>
+        /// <param name="culture">The current culture.</param>
+        /// <returns>The <see cref="Size"/>.</returns>
+        public static Size Parse(string s, CultureInfo culture)
+        {
+            var parts = s.Split(new[] { ',', ' ' }, StringSplitOptions.RemoveEmptyEntries)
+                .Select(x => x.Trim())
+                .ToList();
+
+            if (parts.Count == 2)
+            {
+                return new Size(double.Parse(parts[0], culture), double.Parse(parts[1], culture));
+            }
+            else
+            {
+                throw new FormatException("Invalid Size.");
+            }
+        }
+
         /// <summary>
         /// Constrains the size.
         /// </summary>
@@ -227,4 +250,4 @@ namespace Perspex
             return string.Format(CultureInfo.InvariantCulture, "{0}, {1}", _width, _height);
         }
     }
-}
+}
\ No newline at end of file
diff --git a/src/Shared/PlatformSupport/AssetLoader.cs b/src/Shared/PlatformSupport/AssetLoader.cs
index 86a4bee418..cc60f6de9c 100644
--- a/src/Shared/PlatformSupport/AssetLoader.cs
+++ b/src/Shared/PlatformSupport/AssetLoader.cs
@@ -15,26 +15,6 @@ namespace Perspex.Shared.PlatformSupport
     /// </summary>
     public class AssetLoader : IAssetLoader
     {
-        class AssemblyDescriptor
-        {
-            public AssemblyDescriptor(Assembly assembly)
-            {
-                Assembly = assembly;
-
-                if (assembly != null)
-                {
-                    Resources = assembly.GetManifestResourceNames()
-                        .ToDictionary(n => n, n => (IAssetDescriptor)new AssemblyResourceDescriptor(assembly, n));
-                    Name = assembly.GetName().Name;
-                }
-            }
-
-            public Assembly Assembly { get; }
-            public Dictionary<string, IAssetDescriptor> Resources { get; }
-            public string Name { get; }
-        }
-
-
         private static readonly Dictionary<string, AssemblyDescriptor> AssemblyNameCache
             = new Dictionary<string, AssemblyDescriptor>();
 
@@ -53,7 +33,94 @@ namespace Perspex.Shared.PlatformSupport
             _defaultAssembly = new AssemblyDescriptor(assembly);
         }
 
-        AssemblyDescriptor GetAssembly(string name)
+        /// <summary>
+        /// Checks if an asset with the specified URI exists.
+        /// </summary>
+        /// <param name="uri">The URI.</param>
+        /// <param name="baseUri">
+        /// A base URI to use if <paramref name="uri"/> is relative.
+        /// </param>
+        /// <returns>True if the asset could be found; otherwise false.</returns>
+        public bool Exists(Uri uri, Uri baseUri = null)
+        {
+            return GetAsset(uri, baseUri) != null;
+        }
+
+        /// <summary>
+        /// Opens the resource with the requested URI.
+        /// </summary>
+        /// <param name="uri">The URI.</param>
+        /// <param name="baseUri">
+        /// A base URI to use if <paramref name="uri"/> is relative.
+        /// </param>
+        /// <returns>A stream containing the resource contents.</returns>
+        /// <exception cref="FileNotFoundException">
+        /// The resource was not found.
+        /// </exception>
+        public Stream Open(Uri uri, Uri baseUri = null)
+        {
+            var asset = GetAsset(uri, baseUri);
+
+            if (asset == null)
+            {
+                throw new FileNotFoundException($"The resource {uri} could not be found.");
+            }
+
+            return asset.GetStream();
+        }
+
+        private IAssetDescriptor GetAsset(Uri uri, Uri baseUri)
+        {
+            if (!uri.IsAbsoluteUri || uri.Scheme == "resm")
+            {
+                var uriQueryParams = ParseQueryString(uri);
+                var baseUriQueryParams = uri != null ? ParseQueryString(uri) : null;
+                var asm = GetAssembly(uri) ?? GetAssembly(baseUri) ?? _defaultAssembly;
+
+                if (asm == null && _defaultAssembly == null)
+                {
+                    throw new ArgumentException(
+                        "No default assembly, entry assembly or explicit assembly specified; " +
+                        "don't know where to look up for the resource, try specifiyng assembly explicitly.");
+                }
+
+                IAssetDescriptor rv;
+
+                var resourceKey = uri.AbsolutePath;
+
+#if __IOS__
+                // TODO: HACK: to get iOS up and running. Using Shared projects for resources
+                // is flawed as this alters the reource key locations across platforms
+                // I think we need to use Portable libraries from now on to avoid that.
+                if(asm.Name.Contains("iOS"))
+                {
+                    resourceKey = resourceKey.Replace("TestApplication", "Perspex.iOSTestApplication");
+                }
+#endif
+
+                asm.Resources.TryGetValue(resourceKey, out rv);
+                return rv;
+            }
+            throw new ArgumentException($"Invalid uri, see https://github.com/Perspex/Perspex/issues/282#issuecomment-166982104", nameof(uri));
+        }
+
+        private AssemblyDescriptor GetAssembly(Uri uri)
+        {
+            if (uri != null)
+            {
+                var qs = ParseQueryString(uri);
+                string assemblyName;
+
+                if (qs.TryGetValue("assembly", out assemblyName))
+                {
+                    return GetAssembly(assemblyName);
+                }
+            }
+
+            return null;
+        }
+
+        private AssemblyDescriptor GetAssembly(string name)
         {
             if (name == null)
             {
@@ -82,13 +149,20 @@ namespace Perspex.Shared.PlatformSupport
             return rv;
         }
 
-        interface IAssetDescriptor
+        private Dictionary<string, string> ParseQueryString(Uri uri)
         {
-            Stream GetStream();
+            return uri.Query.TrimStart('?')
+                .Split(new[] { '&' }, StringSplitOptions.RemoveEmptyEntries)
+                .Select(p => p.Split('='))
+                .ToDictionary(p => p[0], p => p[1]);
         }
 
+        private interface IAssetDescriptor
+        {
+            Stream GetStream();
+        }
 
-        class AssemblyResourceDescriptor : IAssetDescriptor
+        private class AssemblyResourceDescriptor : IAssetDescriptor
         {
             private readonly Assembly _asm;
             private readonly string _name;
@@ -104,69 +178,24 @@ namespace Perspex.Shared.PlatformSupport
                 return _asm.GetManifestResourceStream(_name);
             }
         }
-        
 
-        IAssetDescriptor GetAsset(Uri uri)
+        private class AssemblyDescriptor
         {
-            if (!uri.IsAbsoluteUri || uri.Scheme == "resm")
+            public AssemblyDescriptor(Assembly assembly)
             {
-                var qs = uri.Query.TrimStart('?')
-                    .Split(new[] {'&'}, StringSplitOptions.RemoveEmptyEntries)
-                    .Select(p => p.Split('='))
-                    .ToDictionary(p => p[0], p => p[1]);
-                //TODO: Replace _defaultAssembly by current one (need support from OmniXAML)
-                var asm = _defaultAssembly;
-                if (qs.ContainsKey("assembly"))
-                    asm = GetAssembly(qs["assembly"]);
-
-                if (asm == null && _defaultAssembly == null)
-                    throw new ArgumentException(
-                        "No defaultAssembly, entry assembly or explicit assembly specified, don't know where to look up for the resource, try specifiyng assembly explicitly");
-
-                IAssetDescriptor rv;
-
-                var resourceKey = uri.AbsolutePath;
+                Assembly = assembly;
 
-#if __IOS__
-                // TODO: HACK: to get iOS up and running. Using Shared projects for resources
-                // is flawed as this alters the reource key locations across platforms
-                // I think we need to use Portable libraries from now on to avoid that.
-                if(asm.Name.Contains("iOS"))
+                if (assembly != null)
                 {
-                    resourceKey = resourceKey.Replace("TestApplication", "Perspex.iOSTestApplication");
+                    Resources = assembly.GetManifestResourceNames()
+                        .ToDictionary(n => n, n => (IAssetDescriptor)new AssemblyResourceDescriptor(assembly, n));
+                    Name = assembly.GetName().Name;
                 }
-#endif
-
-                asm.Resources.TryGetValue(resourceKey, out rv);
-                return rv;
             }
-            throw new ArgumentException($"Invalid uri, see https://github.com/Perspex/Perspex/issues/282#issuecomment-166982104", nameof(uri));
-        }
-
-        /// <summary>
-        /// Checks if an asset with the specified URI exists.
-        /// </summary>
-        /// <param name="uri">The URI.</param>
-        /// <returns>True if the asset could be found; otherwise false.</returns>
-        public bool Exists(Uri uri)
-        {
-            return GetAsset(uri) != null;
-        }
 
-        /// <summary>
-        /// Opens the resource with the requested URI.
-        /// </summary>
-        /// <param name="uri">The URI.</param>
-        /// <returns>A stream containing the resource contents.</returns>
-        /// <exception cref="FileNotFoundException">
-        /// The resource was not found.
-        /// </exception>
-        public Stream Open(Uri uri)
-        {
-            var asset = GetAsset(uri);
-            if (asset == null)
-                throw new FileNotFoundException($"The resource {uri} could not be found.");
-            return asset.GetStream();
+            public Assembly Assembly { get; }
+            public Dictionary<string, IAssetDescriptor> Resources { get; }
+            public string Name { get; }
         }
     }
 }
diff --git a/src/Skia/Perspex.Skia.Android.TestApp/Perspex.Skia.Android.TestApp.csproj b/src/Skia/Perspex.Skia.Android.TestApp/Perspex.Skia.Android.TestApp.csproj
index 36cb4b0e0b..5a2d675ad6 100644
--- a/src/Skia/Perspex.Skia.Android.TestApp/Perspex.Skia.Android.TestApp.csproj
+++ b/src/Skia/Perspex.Skia.Android.TestApp/Perspex.Skia.Android.TestApp.csproj
@@ -15,7 +15,7 @@
     <AndroidApplication>true</AndroidApplication>
     <AndroidResgenFile>Resources\Resource.Designer.cs</AndroidResgenFile>
     <GenerateSerializationAssemblies>Off</GenerateSerializationAssemblies>
-    <AndroidUseLatestPlatformSdk>True</AndroidUseLatestPlatformSdk>
+    <AndroidUseLatestPlatformSdk>False</AndroidUseLatestPlatformSdk>
     <TargetFrameworkVersion>v5.0</TargetFrameworkVersion>
     <AndroidManifest>Properties\AndroidManifest.xml</AndroidManifest>
   </PropertyGroup>
diff --git a/src/Skia/Perspex.Skia.Android/Perspex.Skia.Android.csproj b/src/Skia/Perspex.Skia.Android/Perspex.Skia.Android.csproj
index 92a3012ad7..469fcddc79 100644
--- a/src/Skia/Perspex.Skia.Android/Perspex.Skia.Android.csproj
+++ b/src/Skia/Perspex.Skia.Android/Perspex.Skia.Android.csproj
@@ -14,7 +14,7 @@
     <FileAlignment>512</FileAlignment>
     <AndroidResgenFile>Resources\Resource.Designer.cs</AndroidResgenFile>
     <GenerateSerializationAssemblies>Off</GenerateSerializationAssemblies>
-    <AndroidUseLatestPlatformSdk>True</AndroidUseLatestPlatformSdk>
+    <AndroidUseLatestPlatformSdk>False</AndroidUseLatestPlatformSdk>
     <TargetFrameworkVersion>v5.0</TargetFrameworkVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
@@ -40,7 +40,7 @@
     <Reference Include="Mono.Android" />
     <Reference Include="mscorlib" />
     <Reference Include="SkiaSharp, Version=1.49.0.0, Culture=neutral, processorArchitecture=MSIL">
-      <HintPath>..\..\..\packages\SkiaSharp.1.49.2.0-beta\lib\MonoAndroid\SkiaSharp.dll</HintPath>
+      <HintPath>..\..\..\packages\SkiaSharp.1.49.2.1-beta\lib\MonoAndroid\SkiaSharp.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <Reference Include="System" />
diff --git a/src/Skia/Perspex.Skia.Android/packages.config b/src/Skia/Perspex.Skia.Android/packages.config
index c0f3883e68..050c885479 100644
--- a/src/Skia/Perspex.Skia.Android/packages.config
+++ b/src/Skia/Perspex.Skia.Android/packages.config
@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="SkiaSharp" version="1.49.2.0-beta" targetFramework="monoandroid60" />
+  <package id="SkiaSharp" version="1.49.2.1-beta" targetFramework="monoandroid50" />
 </packages>
\ No newline at end of file
diff --git a/src/Skia/Perspex.Skia.Desktop/Perspex.Skia.Desktop.csproj b/src/Skia/Perspex.Skia.Desktop/Perspex.Skia.Desktop.csproj
index 499963c1d2..5ea8021734 100644
--- a/src/Skia/Perspex.Skia.Desktop/Perspex.Skia.Desktop.csproj
+++ b/src/Skia/Perspex.Skia.Desktop/Perspex.Skia.Desktop.csproj
@@ -57,7 +57,7 @@
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="SkiaSharp, Version=1.49.0.0, Culture=neutral, processorArchitecture=MSIL">
-      <HintPath>..\..\..\packages\SkiaSharp.1.49.2.0-beta\lib\net45\SkiaSharp.dll</HintPath>
+      <HintPath>..\..\..\packages\SkiaSharp.1.49.2.1-beta\lib\net45\SkiaSharp.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <Reference Include="System" />
@@ -116,12 +116,12 @@
   <Import Project="..\Perspex.Skia\Perspex.Skia.projitems" Label="Shared" />
   <Import Project="..\..\Shared\RenderHelpers\RenderHelpers.projitems" Label="Shared" />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
-  <Import Project="..\..\..\packages\SkiaSharp.1.49.2.0-beta\build\net45\SkiaSharp.targets" Condition="Exists('..\..\..\packages\SkiaSharp.1.49.2.0-beta\build\net45\SkiaSharp.targets')" />
+  <Import Project="..\..\..\packages\SkiaSharp.1.49.2.1-beta\build\net45\SkiaSharp.targets" Condition="Exists('..\..\..\packages\SkiaSharp.1.49.2.1-beta\build\net45\SkiaSharp.targets')" />
   <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
     <PropertyGroup>
       <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
     </PropertyGroup>
-    <Error Condition="!Exists('..\..\..\packages\SkiaSharp.1.49.2.0-beta\build\net45\SkiaSharp.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\..\..\packages\SkiaSharp.1.49.2.0-beta\build\net45\SkiaSharp.targets'))" />
+    <Error Condition="!Exists('..\..\..\packages\SkiaSharp.1.49.2.1-beta\build\net45\SkiaSharp.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\..\..\packages\SkiaSharp.1.49.2.1-beta\build\net45\SkiaSharp.targets'))" />
   </Target>
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
diff --git a/src/Skia/Perspex.Skia.Desktop/packages.config b/src/Skia/Perspex.Skia.Desktop/packages.config
index aa192941cd..a2d6225904 100644
--- a/src/Skia/Perspex.Skia.Desktop/packages.config
+++ b/src/Skia/Perspex.Skia.Desktop/packages.config
@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="SkiaSharp" version="1.49.2.0-beta" targetFramework="net45" />
+  <package id="SkiaSharp" version="1.49.2.1-beta" targetFramework="net45" />
 </packages>
\ No newline at end of file
diff --git a/src/Skia/Perspex.Skia.iOS/Perspex.Skia.iOS.csproj b/src/Skia/Perspex.Skia.iOS/Perspex.Skia.iOS.csproj
index 572d466de5..07c96d5904 100644
--- a/src/Skia/Perspex.Skia.iOS/Perspex.Skia.iOS.csproj
+++ b/src/Skia/Perspex.Skia.iOS/Perspex.Skia.iOS.csproj
@@ -41,7 +41,7 @@
   </ItemGroup>
   <ItemGroup>
     <Reference Include="SkiaSharp, Version=1.49.0.0, Culture=neutral, processorArchitecture=MSIL">
-      <HintPath>..\..\..\packages\SkiaSharp.1.49.2.0-beta\lib\XamariniOS\SkiaSharp.dll</HintPath>
+      <HintPath>..\..\..\packages\SkiaSharp.1.49.2.1-beta\lib\XamariniOS\SkiaSharp.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <Reference Include="System" />
diff --git a/src/Skia/Perspex.Skia.iOS/packages.config b/src/Skia/Perspex.Skia.iOS/packages.config
index 33db31775b..cad65f14ba 100644
--- a/src/Skia/Perspex.Skia.iOS/packages.config
+++ b/src/Skia/Perspex.Skia.iOS/packages.config
@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="SkiaSharp" version="1.49.2.0-beta" targetFramework="xamarinios10" />
+  <package id="SkiaSharp" version="1.49.2.1-beta" targetFramework="xamarinios10" />
 </packages>
\ No newline at end of file
diff --git a/src/Skia/Perspex.Skia/DrawingContextImpl.cs b/src/Skia/Perspex.Skia/DrawingContextImpl.cs
index 49d627442b..970ecfbb2f 100644
--- a/src/Skia/Perspex.Skia/DrawingContextImpl.cs
+++ b/src/Skia/Perspex.Skia/DrawingContextImpl.cs
@@ -229,10 +229,7 @@ namespace Perspex.Skia
                 }
                 else
                 {
-                    // TODO: DrawRRect (ore DrawRoundedRect) is not accesible in SkiaSharp yet. We should add that
-                    // to SkiaSharp and initiate a PR....
-                    Canvas.DrawRect(rc, paint.Paint);
-                    //Canvas.DrawRoundedRect(rc, cornerRadius, cornerRadius, paint);
+                    Canvas.DrawRoundRect(rc, cornerRadius, cornerRadius, paint.Paint);
                 }
             }
         }
@@ -248,10 +245,7 @@ namespace Perspex.Skia
                 }
                 else
                 {
-                    // TODO: this does not exist in SkiaSharp yet
-                    //throw new NotImplementedException();
-                    //Canvas.DrawRoundedRect(rc, cornerRadius, cornerRadius, paint);
-                    Canvas.DrawRect(rc, paint.Paint);
+                    Canvas.DrawRoundRect(rc, cornerRadius, cornerRadius, paint.Paint);
                 }
             }
         }
diff --git a/src/Skia/Perspex.Skia/SkiaSharpExtensions.cs b/src/Skia/Perspex.Skia/SkiaSharpExtensions.cs
index a46f37f6ab..1cb0c710be 100644
--- a/src/Skia/Perspex.Skia/SkiaSharpExtensions.cs
+++ b/src/Skia/Perspex.Skia/SkiaSharpExtensions.cs
@@ -65,5 +65,10 @@ namespace Perspex.Skia
                 case TextAlignment.Right: return SKTextAlign.Right;
             }
         }
+
+        public static SKPath Clone(this SKPath src)
+        {
+            return src != null ? new SKPath(src) : null;
+        }
     }
 }
diff --git a/src/Skia/Perspex.Skia/StreamGeometryImpl.cs b/src/Skia/Perspex.Skia/StreamGeometryImpl.cs
index b5a7f9e3c9..ea704f7e38 100644
--- a/src/Skia/Perspex.Skia/StreamGeometryImpl.cs
+++ b/src/Skia/Perspex.Skia/StreamGeometryImpl.cs
@@ -50,28 +50,23 @@ namespace Perspex.Skia
                 _transformedPath.Dispose();
                 _transformedPath = null;
             }
-            
-            // TODO: SkiaSharp does not expose Transform yet!!!
-            //if (!Transform.IsIdentity)
-            //{
-            //	_transformedPath = new SKPath();
-            //	_path.Transform(Transform.ToSKMatrix(), _transformedPath);
-            //}
+
+            if (!Transform.IsIdentity)
+            {
+                _transformedPath = new SKPath(_path);
+                _transformedPath.Transform(Transform.ToSKMatrix());
+            }
         }
 
         public IStreamGeometryImpl Clone()
         {
-            // TODO: there is no SKPath.Clone yet!!!!!!!!!!!!!
-            //
-            //return new StreamGeometryImpl
-            //{
-            //	_path = _path?.Clone(),
-            //	_transformedPath = _transformedPath?.Clone(),
-            //	_transform = Transform,
-            //	Bounds = Bounds
-            //};
-
-            return this;        // this will probably end bad!!
+            return new StreamGeometryImpl
+            {
+                _path = _path?.Clone(),
+                _transformedPath = _transformedPath?.Clone(),
+                _transform = Transform,
+                Bounds = Bounds
+            };
         }
 
         public IStreamGeometryContextImpl Open()
@@ -94,15 +89,6 @@ namespace Perspex.Skia
 
             public void Dispose()
             {
-                // TODO: Not sure what we need to do here. This code left here for reference.
-                //
-                //	var arr = _elements.ToArray();
-                //             SkRect rc;
-                //             _path?.Dispose();
-                //             _path = new SKPath(new SkPath(MethodTable.Instance.CreatePath(arr, arr.Length, out rc)));
-                //             _geometryImpl.ApplyTransform();
-                //             _geometryImpl.Bounds = rc.ToRect();
-
                 SKRect rc;
                 _path.GetBounds(out rc);
                 _geometryImpl.ApplyTransform();
diff --git a/src/Skia/Perspex.Skia/readme.md b/src/Skia/Perspex.Skia/readme.md
index 1c923df3c5..7c20cf6c2e 100644
--- a/src/Skia/Perspex.Skia/readme.md
+++ b/src/Skia/Perspex.Skia/readme.md
@@ -5,7 +5,6 @@ BitmapImpl
 - Save
 
 DrawingContextImpl
-- DrawRoundRect is not properly implemented due to lack of support in SkiaSharp
 - Alpha support missing as SkiaSharp does not expose this
 - Gradient Shader caching?
 - TileBrushes
@@ -18,12 +17,6 @@ RenderTarget
 - Figure out a cleaner implementation across all platforms
 - HW acceleration
 
-StreamGeometry
-- Paths within Paths may not work right
-- Paths cannot be Cloned (lack of SkiaSupport)
-- Paths cannot be transformed (lack of SkiaSupport)
-- ArcTo
-
 App Bootstrapping
 - Cleanup the testapplications across all platforms
 - Add a cleaner Fluent API for the subsystems
diff --git a/src/Windows/Perspex.Direct2D1/Media/StreamGeometryContextImpl.cs b/src/Windows/Perspex.Direct2D1/Media/StreamGeometryContextImpl.cs
index 8dc3c6231d..5169afce8f 100644
--- a/src/Windows/Perspex.Direct2D1/Media/StreamGeometryContextImpl.cs
+++ b/src/Windows/Perspex.Direct2D1/Media/StreamGeometryContextImpl.cs
@@ -5,6 +5,7 @@ using Perspex.Media;
 using Perspex.Platform;
 using SharpDX.Direct2D1;
 using SweepDirection = SharpDX.Direct2D1.SweepDirection;
+using D2D = SharpDX.Direct2D1;
 
 namespace Perspex.Direct2D1.Media
 {
@@ -24,7 +25,7 @@ namespace Perspex.Direct2D1.Media
             bool isLargeArc,
             Perspex.Media.SweepDirection sweepDirection)
         {
-            _sink.AddArc(new ArcSegment
+            _sink.AddArc(new D2D.ArcSegment
             {
                 Point = point.ToSharpDX(),
                 Size = size.ToSharpDX(),
@@ -41,7 +42,7 @@ namespace Perspex.Direct2D1.Media
 
         public void CubicBezierTo(Point point1, Point point2, Point point3)
         {
-            _sink.AddBezier(new BezierSegment
+            _sink.AddBezier(new D2D.BezierSegment
             {
                 Point1 = point1.ToSharpDX(),
                 Point2 = point2.ToSharpDX(),
@@ -51,7 +52,7 @@ namespace Perspex.Direct2D1.Media
 
         public void QuadraticBezierTo(Point control, Point dest)
         {
-            _sink.AddQuadraticBezier(new QuadraticBezierSegment
+            _sink.AddQuadraticBezier(new D2D.QuadraticBezierSegment
             {
                 Point1 = control.ToSharpDX(),
                 Point2 = dest.ToSharpDX()
diff --git a/src/Windows/Perspex.Direct2D1/Media/StreamGeometryImpl.cs b/src/Windows/Perspex.Direct2D1/Media/StreamGeometryImpl.cs
index f9f790db56..be0df4712d 100644
--- a/src/Windows/Perspex.Direct2D1/Media/StreamGeometryImpl.cs
+++ b/src/Windows/Perspex.Direct2D1/Media/StreamGeometryImpl.cs
@@ -1,7 +1,6 @@
 // Copyright (c) The Perspex Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
-using Perspex.Media;
 using Perspex.Platform;
 using SharpDX.Direct2D1;
 using D2DGeometry = SharpDX.Direct2D1.Geometry;
diff --git a/tests/Perspex.Base.UnitTests/PerspexObjectTests_Direct.cs b/tests/Perspex.Base.UnitTests/PerspexObjectTests_Direct.cs
index 09f42ee045..fab76d4555 100644
--- a/tests/Perspex.Base.UnitTests/PerspexObjectTests_Direct.cs
+++ b/tests/Perspex.Base.UnitTests/PerspexObjectTests_Direct.cs
@@ -344,6 +344,7 @@ namespace Perspex.Base.UnitTests
             {
                 var source = new Subject<string>();
                 var sub = target.Bind((PerspexProperty)Class1.FooProperty, source);
+                source.OnNext("foo");
                 return new WeakReference(source);
             };
 
@@ -351,6 +352,7 @@ namespace Perspex.Base.UnitTests
 
             GC.Collect();
 
+            Assert.Equal("foo", target.Foo);
             Assert.True(weakSource.IsAlive);
         }
 
diff --git a/tests/Perspex.Controls.UnitTests/ListBoxTests.cs b/tests/Perspex.Controls.UnitTests/ListBoxTests.cs
index a502d3b186..82702adef8 100644
--- a/tests/Perspex.Controls.UnitTests/ListBoxTests.cs
+++ b/tests/Perspex.Controls.UnitTests/ListBoxTests.cs
@@ -104,30 +104,6 @@ namespace Perspex.Controls.UnitTests
                 dataContexts);
         }
 
-        [Fact]
-        public void Setting_SelectedItem_Should_Set_Panel_Keyboard_Navigation()
-        {
-            var target = new ListBox
-            {
-                Template = new FuncControlTemplate(CreateListBoxTemplate),
-                Items = new[] { "Foo", "Bar", "Baz " },
-            };
-
-            ApplyTemplate(target);
-
-            target.Presenter.Panel.Children[1].RaiseEvent(new PointerPressedEventArgs
-            {
-                RoutedEvent = InputElement.PointerPressedEvent,
-                MouseButton = MouseButton.Left,
-            });
-
-            var panel = target.Presenter.Panel;
-
-            Assert.Equal(
-                KeyboardNavigation.GetTabOnceActiveElement((InputElement)panel),
-                panel.Children[1]);
-        }
-
         private Control CreateListBoxTemplate(ITemplatedControl parent)
         {
             return new ScrollViewer
diff --git a/tests/Perspex.Controls.UnitTests/Presenters/CarouselPresenterTests.cs b/tests/Perspex.Controls.UnitTests/Presenters/CarouselPresenterTests.cs
index 31aebb6124..0c092943d4 100644
--- a/tests/Perspex.Controls.UnitTests/Presenters/CarouselPresenterTests.cs
+++ b/tests/Perspex.Controls.UnitTests/Presenters/CarouselPresenterTests.cs
@@ -7,6 +7,7 @@ using Perspex.Controls.Generators;
 using Perspex.Controls.Presenters;
 using Perspex.Controls.Templates;
 using Xunit;
+using System.Collections.ObjectModel;
 
 namespace Perspex.Controls.UnitTests.Presenters
 {
@@ -116,6 +117,82 @@ namespace Perspex.Controls.UnitTests.Presenters
             Assert.Equal(2, target.Panel.Children.Count);
         }
 
+        [Fact]
+        public void Should_Remove_Controls_When_IsVirtualized_Is_False()
+        {
+            ObservableCollection<string> items = new ObservableCollection<string>();
+            
+            var target = new CarouselPresenter
+            {
+                Items = items,              
+                SelectedIndex = 0,
+                IsVirtualized = false,
+            };
+
+            target.ApplyTemplate();
+            target.SelectedIndex = 0;
+            items.Add("foo");
+            target.SelectedIndex = 0;
+
+            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
+            Assert.Equal(1, target.Panel.Children.Count);
+
+            items.Add("bar");
+            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
+            Assert.Equal(1, target.Panel.Children.Count);
+
+            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);            
+
+            items.Remove(items[0]);
+            Assert.Equal(0, target.ItemContainerGenerator.Containers.Count());
+            Assert.Equal(0, target.Panel.Children.Count);            
+        }
+
+        [Fact]
+        public void Should_have_correct_index_itemscontainer()
+        {
+            ObservableCollection<string> items = new ObservableCollection<string>();
+
+            var target = new CarouselPresenter
+            {
+                Items = items,
+                SelectedIndex = 0,
+                IsVirtualized = false,
+            };
+
+            target.ApplyTemplate();
+            target.SelectedIndex = 0;
+            items.Add("foo");
+            target.SelectedIndex = 0;
+
+            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
+            Assert.Equal(1, target.Panel.Children.Count);
+
+            items.Add("bar");
+            Assert.Equal(1, target.ItemContainerGenerator.Containers.Count());
+            Assert.Equal(1, target.Panel.Children.Count);
+
+            target.SelectedIndex = 1;
+            Assert.Equal(2, target.ItemContainerGenerator.Containers.Count());
+            Assert.Equal(2, target.Panel.Children.Count);
+            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.Equal(1, target.ItemContainerGenerator.Containers.First().Index);
+
+            items.Remove(items[0]);
+            Assert.Equal(0, target.ItemContainerGenerator.Containers.Count());
+            Assert.Equal(0, target.Panel.Children.Count);            
+        }
+
         private class TestItem : ContentControl
         {
         }
diff --git a/tests/Perspex.Controls.UnitTests/Primitives/SelectingItemsControlTests.cs b/tests/Perspex.Controls.UnitTests/Primitives/SelectingItemsControlTests.cs
index 361d6a5d08..46fba11250 100644
--- a/tests/Perspex.Controls.UnitTests/Primitives/SelectingItemsControlTests.cs
+++ b/tests/Perspex.Controls.UnitTests/Primitives/SelectingItemsControlTests.cs
@@ -8,6 +8,7 @@ using Perspex.Collections;
 using Perspex.Controls.Presenters;
 using Perspex.Controls.Primitives;
 using Perspex.Controls.Templates;
+using Perspex.Input;
 using Perspex.Interactivity;
 using Perspex.Markup.Xaml.Data;
 using Perspex.UnitTests;
@@ -604,6 +605,57 @@ namespace Perspex.Controls.UnitTests.Primitives
             Assert.Equal(0, root.SelectedIndex);
         }
 
+        [Fact]
+        public void Setting_SelectedItem_With_Pointer_Should_Set_TabOnceActiveElement()
+        {
+            var target = new ListBox
+            {
+                Template = Template(),
+                Items = new[] { "Foo", "Bar", "Baz " },
+            };
+
+            target.ApplyTemplate();
+            target.Presenter.ApplyTemplate();
+
+            target.Presenter.Panel.Children[1].RaiseEvent(new PointerPressedEventArgs
+            {
+                RoutedEvent = InputElement.PointerPressedEvent,
+                MouseButton = MouseButton.Left,
+            });
+
+            var panel = target.Presenter.Panel;
+
+            Assert.Equal(
+                KeyboardNavigation.GetTabOnceActiveElement((InputElement)panel),
+                panel.Children[1]);
+        }
+
+        [Fact]
+        public void Removing_SelectedItem_Should_Clear_TabOnceActiveElement()
+        {
+            var items = new ObservableCollection<string>(new[] { "Foo", "Bar", "Baz " });
+
+            var target = new ListBox
+            {
+                Template = Template(),
+                Items = items,
+            };
+
+            target.ApplyTemplate();
+            target.Presenter.ApplyTemplate();
+
+            target.Presenter.Panel.Children[1].RaiseEvent(new PointerPressedEventArgs
+            {
+                RoutedEvent = InputElement.PointerPressedEvent,
+                MouseButton = MouseButton.Left,
+            });
+
+            items.RemoveAt(1);
+
+            var panel = target.Presenter.Panel;
+
+            Assert.Null(KeyboardNavigation.GetTabOnceActiveElement((InputElement)panel));
+        }
 
         private FuncControlTemplate Template()
         {
diff --git a/tests/Perspex.Input.UnitTests/InputElement_Focus.cs b/tests/Perspex.Input.UnitTests/InputElement_Focus.cs
new file mode 100644
index 0000000000..a3016cdd8a
--- /dev/null
+++ b/tests/Perspex.Input.UnitTests/InputElement_Focus.cs
@@ -0,0 +1,49 @@
+// Copyright (c) The Perspex Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using Perspex.Controls;
+using Perspex.UnitTests;
+using Xunit;
+
+namespace Perspex.Input.UnitTests
+{
+    public class InputElement_Focus
+    {
+        [Fact]
+        public void Focus_Should_Set_FocusManager_Current()
+        {
+            Button target;
+
+            using (UnitTestApplication.Start(TestServices.RealFocus))
+            {
+                var root = new TestRoot
+                {
+                    Child = target = new Button()
+                };
+
+                target.Focus();
+
+                Assert.Same(target, FocusManager.Instance.Current);
+            }
+        }
+
+        [Fact]
+        public void Focus_Should_Be_Cleared_When_Control_Is_Removed_From_VisualTree()
+        {
+            Button target;
+
+            using (UnitTestApplication.Start(TestServices.RealFocus))
+            {
+                var root = new TestRoot
+                {
+                    Child = target = new Button()
+                };
+
+                target.Focus();
+                root.Child = null;
+
+                Assert.Null(FocusManager.Instance.Current);
+            }
+        }
+    }
+}
diff --git a/tests/Perspex.Input.UnitTests/Perspex.Input.UnitTests.csproj b/tests/Perspex.Input.UnitTests/Perspex.Input.UnitTests.csproj
index e41c379026..d1b4bba60b 100644
--- a/tests/Perspex.Input.UnitTests/Perspex.Input.UnitTests.csproj
+++ b/tests/Perspex.Input.UnitTests/Perspex.Input.UnitTests.csproj
@@ -60,6 +60,7 @@
     </Reference>
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="InputElement_Focus.cs" />
     <Compile Include="InputElement_HitTesting.cs" />
     <Compile Include="KeyboardNavigationTests_Arrows.cs" />
     <Compile Include="KeyboardNavigationTests_Tab.cs" />
@@ -103,6 +104,10 @@
       <Project>{F1BAA01A-F176-4C6A-B39D-5B40BB1B148F}</Project>
       <Name>Perspex.Styling</Name>
     </ProjectReference>
+    <ProjectReference Include="..\Perspex.UnitTests\Perspex.UnitTests.csproj">
+      <Project>{88060192-33D5-4932-B0F9-8BD2763E857D}</Project>
+      <Name>Perspex.UnitTests</Name>
+    </ProjectReference>
   </ItemGroup>
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
diff --git a/tests/Perspex.UnitTests/TestRoot.cs b/tests/Perspex.UnitTests/TestRoot.cs
index 84a4a15aa7..48b8beaeba 100644
--- a/tests/Perspex.UnitTests/TestRoot.cs
+++ b/tests/Perspex.UnitTests/TestRoot.cs
@@ -3,6 +3,7 @@
 
 using System;
 using Perspex.Controls;
+using Perspex.Input;
 using Perspex.Layout;
 using Perspex.Platform;
 using Perspex.Rendering;
@@ -10,7 +11,7 @@ using Perspex.Styling;
 
 namespace Perspex.UnitTests
 {
-    public class TestRoot : Decorator, ILayoutRoot, INameScope, IRenderRoot, IStyleRoot
+    public class TestRoot : Decorator, IFocusScope, ILayoutRoot, INameScope, IRenderRoot, IStyleRoot
     {
         private readonly NameScope _nameScope = new NameScope();
 
diff --git a/tests/Perspex.UnitTests/TestServices.cs b/tests/Perspex.UnitTests/TestServices.cs
index 6383aeb516..bac9cc1c24 100644
--- a/tests/Perspex.UnitTests/TestServices.cs
+++ b/tests/Perspex.UnitTests/TestServices.cs
@@ -36,12 +36,19 @@ namespace Perspex.UnitTests
         public static readonly TestServices MockThreadingInterface = new TestServices(
             threadingInterface: Mock.Of<IPlatformThreadingInterface>(x => x.CurrentThreadIsLoopThread == true));
 
+        public static readonly TestServices RealFocus = new TestServices(
+            focusManager: new FocusManager(),
+            keyboardDevice: () => new KeyboardDevice(),
+            inputManager: new InputManager());
+
         public static readonly TestServices RealStyler = new TestServices(
             styler: new Styler());
 
         public TestServices(
             IAssetLoader assetLoader = null,
+            IFocusManager focusManager = null,
             IInputManager inputManager = null,
+            Func<IKeyboardDevice> keyboardDevice = null,
             ILayoutManager layoutManager = null,
             IPclPlatformWrapper platformWrapper = null,
             IPlatformRenderInterface renderInterface = null,
@@ -53,7 +60,9 @@ namespace Perspex.UnitTests
             IWindowingPlatform windowingPlatform = null)
         {
             AssetLoader = assetLoader;
+            FocusManager = focusManager;
             InputManager = inputManager;
+            KeyboardDevice = keyboardDevice;
             LayoutManager = layoutManager;
             PlatformWrapper = platformWrapper;
             RenderInterface = renderInterface;
@@ -67,6 +76,8 @@ namespace Perspex.UnitTests
 
         public IAssetLoader AssetLoader { get; }
         public IInputManager InputManager { get; }
+        public IFocusManager FocusManager { get; }
+        public Func<IKeyboardDevice> KeyboardDevice { get; }
         public ILayoutManager LayoutManager { get; }
         public IPclPlatformWrapper PlatformWrapper { get; }
         public IPlatformRenderInterface RenderInterface { get; }
@@ -79,7 +90,9 @@ namespace Perspex.UnitTests
 
         public TestServices With(
             IAssetLoader assetLoader = null,
+            IFocusManager focusManager = null,
             IInputManager inputManager = null,
+            Func<IKeyboardDevice> keyboardDevice = null,
             ILayoutManager layoutManager = null,
             IPclPlatformWrapper platformWrapper = null,
             IPlatformRenderInterface renderInterface = null,
@@ -92,7 +105,9 @@ namespace Perspex.UnitTests
         {
             return new TestServices(
                 assetLoader: assetLoader ?? AssetLoader,
+                focusManager: focusManager ?? FocusManager,
                 inputManager: inputManager ?? InputManager,
+                keyboardDevice: keyboardDevice ?? KeyboardDevice,
                 layoutManager: layoutManager ?? LayoutManager,
                 platformWrapper: platformWrapper ?? PlatformWrapper,
                 renderInterface: renderInterface ?? RenderInterface,
diff --git a/tests/Perspex.UnitTests/UnitTestApplication.cs b/tests/Perspex.UnitTests/UnitTestApplication.cs
index 04fd5daf68..3807a35fdb 100644
--- a/tests/Perspex.UnitTests/UnitTestApplication.cs
+++ b/tests/Perspex.UnitTests/UnitTestApplication.cs
@@ -40,8 +40,10 @@ namespace Perspex.UnitTests
         {
             PerspexLocator.CurrentMutable
                 .Bind<IAssetLoader>().ToConstant(Services.AssetLoader)
+                .Bind<IFocusManager>().ToConstant(Services.FocusManager)
                 .BindToSelf<IGlobalStyles>(this)
                 .Bind<IInputManager>().ToConstant(Services.InputManager)
+                .Bind<IKeyboardDevice>().ToConstant(Services.KeyboardDevice?.Invoke())
                 .Bind<ILayoutManager>().ToConstant(Services.LayoutManager)
                 .Bind<IPclPlatformWrapper>().ToConstant(Services.PlatformWrapper)
                 .Bind<IPlatformRenderInterface>().ToConstant(Services.RenderInterface)