Merge branch 'master' into feature/fluent-progress-bar

# Conflicts:
#	samples/ControlCatalog/App.xaml
#	samples/ControlCatalog/MainView.xaml.cs
#	samples/ControlCatalog/MainWindow.xaml

samples/ControlCatalog/App.xaml

@@ -1,10 +1,7 @@
 <Application xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="ControlCatalog.App">
-  <Application.Styles>
-    <StyleInclude Source="resm:Avalonia.Themes.Default.Accents.BaseDark.xaml?assembly=Avalonia.Themes.Default" />
-    <StyleInclude Source="avares://Avalonia.Themes.Fluent/Accents/FluentDark.xaml"/>
-    <StyleInclude Source="avares://Avalonia.Themes.Fluent/FluentTheme.xaml"/>
+  <Application.Styles>        
     <StyleInclude Source="avares://Avalonia.Controls.DataGrid/Themes/Default.xaml"/>
     <Style Selector="TextBlock.h1">
       <Setter Property="FontSize" Value="{DynamicResource FontSizeLarge}"/>

samples/ControlCatalog/App.xaml.cs

@@ -1,14 +1,67 @@
+using System;
 using Avalonia;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Markup.Xaml;
+using Avalonia.Markup.Xaml.Styling;
+using Avalonia.Styling;
 
 namespace ControlCatalog
 {
     public class App : Application
     {
+        public static Styles FluentDark = new Styles
+        {
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("resm:Avalonia.Themes.Default.Accents.BaseDark.xaml?assembly=Avalonia.Themes.Default")
+            },
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("resm:Avalonia.Themes.Fluent.Accents.FluentDark.xaml?assembly=Avalonia.Themes.Fluent")
+            },
+        };
+
+        public static Styles FluentLight = new Styles
+        {
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("resm:Avalonia.Themes.Default.Accents.BaseLight.xaml?assembly=Avalonia.Themes.Default")
+            },
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("resm:Avalonia.Themes.Fluent.Accents.FluentLight.xaml?assembly=Avalonia.Themes.Fluent")
+            },
+        };
+
+        public static Styles DefaultLight = new Styles
+        {
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("resm:Avalonia.Themes.Default.Accents.BaseLight.xaml?assembly=Avalonia.Themes.Default")
+            },
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("resm:Avalonia.Themes.Default.DefaultTheme.xaml?assembly=Avalonia.Themes.Default")
+            },
+        };
+
+        public static Styles DefaultDark = new Styles
+        {
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("resm:Avalonia.Themes.Default.Accents.BaseDark.xaml?assembly=Avalonia.Themes.Default")
+            },
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("resm:Avalonia.Themes.Default.DefaultTheme.xaml?assembly=Avalonia.Themes.Default")
+            },
+        };
+
         public override void Initialize()
         {
             AvaloniaXamlLoader.Load(this);
+
+            Styles.Insert(0, FluentDark);
         }
 
         public override void OnFrameworkInitializationCompleted()

samples/ControlCatalog/MainView.xaml

@@ -29,7 +29,8 @@
                ScrollViewer.HorizontalScrollBarVisibility="Disabled">
           <pages:DataGridPage/>
       </TabItem>
-      <TabItem Header="DatePicker"><pages:DatePickerPage/></TabItem>
+      <TabItem Header="CalendarDatePicker">
+        <pages:CalendarDatePickerPage/></TabItem>
       <TabItem Header="Drag+Drop"><pages:DragAndDropPage/></TabItem>
       <TabItem Header="Expander"><pages:ExpanderPage/></TabItem>
       <TabItem Header="Image"
@@ -67,8 +68,10 @@
             <ComboBoxItem>Full Decorations</ComboBoxItem>
           </ComboBox>
           <ComboBox x:Name="Themes" SelectedIndex="0">
-            <ComboBoxItem>Light</ComboBoxItem>
-            <ComboBoxItem>Dark</ComboBoxItem>
+            <ComboBoxItem>Fluent - Dark</ComboBoxItem>
+            <ComboBoxItem>Fluent - Light</ComboBoxItem>
+            <ComboBoxItem>Simple - Light</ComboBoxItem>
+            <ComboBoxItem>Simple - Dark</ComboBoxItem>
           </ComboBox>
           <ComboBox x:Name="TransparencyLevels" SelectedIndex="0">
             <ComboBoxItem>None</ComboBoxItem>

samples/ControlCatalog/MainView.xaml.cs

@@ -32,6 +32,26 @@ namespace ControlCatalog
 
             }
 
+            var themes = this.Find<ComboBox>("Themes");
+            themes.SelectionChanged += (sender, e) =>
+            {
+                switch (themes.SelectedIndex)
+                {
+                    case 0:
+                        Application.Current.Styles[0] = App.FluentDark;
+                        break;
+                    case 1:
+                        Application.Current.Styles[0] = App.FluentLight;
+                        break;
+                    case 2:
+                        Application.Current.Styles[0] = App.DefaultLight;
+                        break;
+                    case 3:
+                        Application.Current.Styles[0] = App.DefaultDark;
+                        break;
+                }
+            };            
+
             var decorations = this.Find<ComboBox>("Decorations");
             decorations.SelectionChanged += (sender, e) =>
             {

samples/ControlCatalog/MainWindow.xaml

@@ -7,7 +7,7 @@
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:vm="clr-namespace:ControlCatalog.ViewModels"
         xmlns:v="clr-namespace:ControlCatalog.Views"
-        x:Class="ControlCatalog.MainWindow" WindowState="{Binding WindowState, Mode=TwoWay}">
+        x:Class="ControlCatalog.MainWindow" WindowState="{Binding WindowState, Mode=TwoWay}" Background="{DynamicResource SystemControlPageBackgroundAltHighBrush}">
   <NativeMenu.Menu>
     <NativeMenu>
       <NativeMenuItem Header="File">

samples/ControlCatalog/Pages/ButtonPage.xaml

@@ -24,7 +24,11 @@
             </Style>
           </Button.Styles>          
         </Button>
-      </StackPanel>
+        <RepeatButton Name="RepeatButton">
+          <TextBlock Name="RepeatButtonTextBlock" Text="Repeat Button: 0" />
+        </RepeatButton>
+        <ToggleButton Content="Toggle Button"/>
+    </StackPanel>
 
       <StackPanel Orientation="Vertical" Spacing="8" Width="150">
         <Button BorderThickness="0">No Border</Button>

samples/ControlCatalog/Pages/ButtonPage.xaml.cs

@@ -5,5 +5,25 @@ namespace ControlCatalog.Pages
 {
     public class ButtonPage : UserControl
     {
+        private int repeatButtonClickCount = 0;
+
+        public ButtonPage()
+        {
+            InitializeComponent();
+
+            this.FindControl<RepeatButton>("RepeatButton").Click += OnRepeatButtonClick;
+        }
+
+        private void InitializeComponent()
+        {
+            AvaloniaXamlLoader.Load(this);
+        }
+
+        public void OnRepeatButtonClick(object sender, object args)
+        {
+            repeatButtonClickCount++;
+            var textBlock = this.FindControl<TextBlock>("RepeatButtonTextBlock");
+            textBlock.Text = $"Repeat Button: {repeatButtonClickCount}";
+        }
     }
 }

samples/ControlCatalog/Pages/DatePickerPage.xaml → samples/ControlCatalog/Pages/CalendarDatePickerPage.xaml

@@ -1,8 +1,8 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             x:Class="ControlCatalog.Pages.DatePickerPage">
+             x:Class="ControlCatalog.Pages.CalendarDatePickerPage">
   <StackPanel Orientation="Vertical" Spacing="4">
-    <TextBlock Classes="h1">DatePicker</TextBlock>
+    <TextBlock Classes="h1">CalendarDatePicker</TextBlock>
     <TextBlock Classes="h2">A control for selecting dates with a calendar drop-down</TextBlock>
         
     <StackPanel Orientation="Horizontal"
@@ -12,34 +12,34 @@
       <StackPanel Orientation="Vertical"
                   Width="200">
         <TextBlock Text="SelectedDateFormat: Short"/>
-        <DatePicker Name="DatePicker1"
+        <CalendarDatePicker Name="DatePicker1"
                     SelectedDateFormat="Short"
                     Margin="0,0,0,8"/>
 
         <TextBlock Text="SelectedDateFormat: Long"/>
-        <DatePicker Name="DatePicker2"
+        <CalendarDatePicker Name="DatePicker2"
                     SelectedDateFormat="Long"
                     Margin="0,0,0,8"/>
 
         <TextBlock Text="SelectedDateFormat: Custom"/>
-        <DatePicker Name="DatePicker3"
+        <CalendarDatePicker Name="DatePicker3"
                     SelectedDateFormat="Custom"
                     CustomDateFormatString="ddd, MMM d"
                     Margin="0,0,0,8"/>
 
         <TextBlock Text="Blackout Dates"/>
-        <DatePicker Name="DatePicker4"
+        <CalendarDatePicker Name="DatePicker4"
                     Margin="0,0,0,8"/>
 
-        <DatePicker Margin="0,0,0,8"
+        <CalendarDatePicker Margin="0,0,0,8"
                     Watermark="Watermark"/>
-        <DatePicker Margin="0,0,0,8"
+        <CalendarDatePicker Margin="0,0,0,8"
                     Name="DatePicker5"
                     Watermark="Floating Watermark"
                     UseFloatingWatermark="True"/>
                 
         <TextBlock Text="Disabled"/>
-        <DatePicker IsEnabled="False"/>
+        <CalendarDatePicker IsEnabled="False"/>
       </StackPanel>
 
     </StackPanel> 

samples/ControlCatalog/Pages/DatePickerPage.xaml.cs → samples/ControlCatalog/Pages/CalendarDatePickerPage.xaml.cs

@@ -4,17 +4,17 @@ using System;
 
 namespace ControlCatalog.Pages
 {
-    public class DatePickerPage : UserControl
+    public class CalendarDatePickerPage : UserControl
     {
-        public DatePickerPage()
+        public CalendarDatePickerPage()
         {
             InitializeComponent();
             
-            var dp1 = this.FindControl<DatePicker>("DatePicker1");
-            var dp2 = this.FindControl<DatePicker>("DatePicker2");
-            var dp3 = this.FindControl<DatePicker>("DatePicker3");
-            var dp4 = this.FindControl<DatePicker>("DatePicker4");
-            var dp5 = this.FindControl<DatePicker>("DatePicker5");
+            var dp1 = this.FindControl<CalendarDatePicker>("DatePicker1");
+            var dp2 = this.FindControl<CalendarDatePicker>("DatePicker2");
+            var dp3 = this.FindControl<CalendarDatePicker>("DatePicker3");
+            var dp4 = this.FindControl<CalendarDatePicker>("DatePicker4");
+            var dp5 = this.FindControl<CalendarDatePicker>("DatePicker5");
 
             dp1.SelectedDate = DateTime.Today;
             dp2.SelectedDate = DateTime.Today.AddDays(10);

samples/ControlCatalog/Pages/TreeViewPage.xaml

@@ -20,6 +20,7 @@
 
         <Button Command="{Binding AddItemCommand}">Add</Button>
         <Button Command="{Binding RemoveItemCommand}">Remove</Button>
+        <Button Command="{Binding SelectRandomItemCommand}">Select Random</Button>
 
         <ComboBox SelectedIndex="{Binding SelectionMode, Mode=TwoWay}">
           <ComboBoxItem>Single</ComboBoxItem>

samples/ControlCatalog/ViewModels/TreeViewPageViewModel.cs

@@ -23,12 +23,14 @@ namespace ControlCatalog.ViewModels
 
             AddItemCommand = ReactiveCommand.Create(AddItem);
             RemoveItemCommand = ReactiveCommand.Create(RemoveItem);
+            SelectRandomItemCommand = ReactiveCommand.Create(SelectRandomItem);
         }
 
         public ObservableCollection<Node> Items { get; }
         public SelectionModel Selection { get; }
         public ReactiveCommand<Unit, Unit> AddItemCommand { get; }
         public ReactiveCommand<Unit, Unit> RemoveItemCommand { get; }
+        public ReactiveCommand<Unit, Unit> SelectRandomItemCommand { get; }
 
         public SelectionMode SelectionMode
         {
@@ -74,6 +76,15 @@ namespace ControlCatalog.ViewModels
             }
         }
 
+        private void SelectRandomItem()
+        {
+            var random = new Random();
+            var depth = random.Next(4);
+            var indexes = Enumerable.Range(0, 4).Select(x => random.Next(10));
+            var path = new IndexPath(indexes);
+            Selection.SelectedIndex = path;
+        }
+
         private void SelectionChanged(object sender, SelectionModelSelectionChangedEventArgs e)
         {
             var selected = string.Join(",", e.SelectedIndices);

src/Avalonia.Base/Data/Core/Plugins/InpcPropertyAccessorPlugin.cs

@@ -12,7 +12,7 @@ namespace Avalonia.Data.Core.Plugins
     public class InpcPropertyAccessorPlugin : IPropertyAccessorPlugin
     {
         /// <inheritdoc/>
-        public bool Match(object obj, string propertyName) => true;
+        public bool Match(object obj, string propertyName) => GetPropertyWithName(obj.GetType(), propertyName) != null;
 
         /// <summary>
         /// Starts monitoring the value of a property on an object.
@@ -30,10 +30,7 @@ namespace Avalonia.Data.Core.Plugins
 
             reference.TryGetTarget(out object instance);
 
-            const BindingFlags bindingFlags = BindingFlags.NonPublic | BindingFlags.Public |
-                                              BindingFlags.Static | BindingFlags.Instance;
-
-            var p = instance.GetType().GetProperty(propertyName, bindingFlags);
+            var p = GetPropertyWithName(instance.GetType(), propertyName);
 
             if (p != null)
             {
@@ -47,6 +44,14 @@ namespace Avalonia.Data.Core.Plugins
             }
         }
 
+        private static PropertyInfo GetPropertyWithName(Type type, string propertyName)
+        {
+            const BindingFlags bindingFlags = BindingFlags.NonPublic | BindingFlags.Public |
+                                              BindingFlags.Static | BindingFlags.Instance;
+
+            return type.GetProperty(propertyName, bindingFlags);
+        }
+
         private class Accessor : PropertyAccessorBase, IWeakSubscriber<PropertyChangedEventArgs>
         {
             private readonly WeakReference<object> _reference;

src/Avalonia.Base/Data/Core/PropertyAccessorNode.cs

@@ -62,8 +62,13 @@ namespace Avalonia.Data.Core
 
             if (accessor == null)
             {
-                throw new NotSupportedException(
-                    $"Could not find a matching property accessor for {PropertyName}.");
+                reference.TryGetTarget(out object instance);
+
+                var message = $"Could not find a matching property accessor for '{PropertyName}' on '{instance}'";
+
+                var exception = new MissingMemberException(message);
+
+                accessor = new PropertyError(new BindingNotification(exception, BindingErrorType.Error));
             }
 
             _accessor = accessor;

src/Avalonia.Base/Properties/AssemblyInfo.cs

@@ -7,4 +7,4 @@ using Avalonia.Metadata;
 [assembly: XmlnsDefinition("https://github.com/avaloniaui", "Avalonia.Data.Converters")]
 [assembly: InternalsVisibleTo("Avalonia.Base.UnitTests")]
 [assembly: InternalsVisibleTo("Avalonia.UnitTests")]
-[assembly: InternalsVisibleTo("DynamicProxyGenAssembly2")] 
+[assembly: InternalsVisibleTo("DynamicProxyGenAssembly2")]

src/Avalonia.Base/Utilities/MathUtilities.cs

@@ -8,6 +8,11 @@ namespace Avalonia.Utilities
     /// </summary>
     public static class MathUtilities
     {
+        // smallest such that 1.0+DoubleEpsilon != 1.0
+        private const double DoubleEpsilon = 2.2204460492503131e-016;
+
+        private const float FloatEpsilon = 1.192092896e-07F;
+
         /// <summary>
         /// AreClose - Returns whether or not two doubles are "close".  That is, whether or 
         /// not they are within epsilon of each other.
@@ -18,11 +23,26 @@ namespace Avalonia.Utilities
         {
             //in case they are Infinities (then epsilon check does not work)
             if (value1 == value2) return true;
-            double eps = (Math.Abs(value1) + Math.Abs(value2) + 10.0) * double.Epsilon;
+            double eps = (Math.Abs(value1) + Math.Abs(value2) + 10.0) * DoubleEpsilon;
             double delta = value1 - value2;
             return (-eps < delta) && (eps > delta);
         }
 
+        /// <summary>
+        /// AreClose - Returns whether or not two floats are "close".  That is, whether or 
+        /// not they are within epsilon of each other.
+        /// </summary> 
+        /// <param name="value1"> The first float to compare. </param>
+        /// <param name="value2"> The second float to compare. </param>
+        public static bool AreClose(float value1, float value2)
+        {
+            //in case they are Infinities (then epsilon check does not work)
+            if (value1 == value2) return true;
+            float eps = (Math.Abs(value1) + Math.Abs(value2) + 10.0f) * FloatEpsilon;
+            float delta = value1 - value2;
+            return (-eps < delta) && (eps > delta);
+        }
+
         /// <summary>
         /// LessThan - Returns whether or not the first double is less than the second double.
         /// That is, whether or not the first is strictly less than *and* not within epsilon of
@@ -35,6 +55,18 @@ namespace Avalonia.Utilities
             return (value1 < value2) && !AreClose(value1, value2);
         }
 
+        /// <summary>
+        /// LessThan - Returns whether or not the first float is less than the second float.
+        /// That is, whether or not the first is strictly less than *and* not within epsilon of
+        /// the other number.
+        /// </summary>
+        /// <param name="value1"> The first single float to compare. </param>
+        /// <param name="value2"> The second single float to compare. </param>
+        public static bool LessThan(float value1, float value2)
+        {
+            return (value1 < value2) && !AreClose(value1, value2);
+        }
+
         /// <summary>
         /// GreaterThan - Returns whether or not the first double is greater than the second double.
         /// That is, whether or not the first is strictly greater than *and* not within epsilon of
@@ -47,6 +79,18 @@ namespace Avalonia.Utilities
             return (value1 > value2) && !AreClose(value1, value2);
         }
 
+        /// <summary>
+        /// GreaterThan - Returns whether or not the first float is greater than the second float.
+        /// That is, whether or not the first is strictly greater than *and* not within epsilon of
+        /// the other number.
+        /// </summary>
+        /// <param name="value1"> The first float to compare. </param>
+        /// <param name="value2"> The second float to compare. </param>
+        public static bool GreaterThan(float value1, float value2)
+        {
+            return (value1 > value2) && !AreClose(value1, value2);
+        }
+
         /// <summary>
         /// LessThanOrClose - Returns whether or not the first double is less than or close to
         /// the second double.  That is, whether or not the first is strictly less than or within
@@ -59,6 +103,18 @@ namespace Avalonia.Utilities
             return (value1 < value2) || AreClose(value1, value2);
         }
 
+        /// <summary>
+        /// LessThanOrClose - Returns whether or not the first float is less than or close to
+        /// the second float.  That is, whether or not the first is strictly less than or within
+        /// epsilon of the other number.
+        /// </summary>
+        /// <param name="value1"> The first float to compare. </param>
+        /// <param name="value2"> The second float to compare. </param>
+        public static bool LessThanOrClose(float value1, float value2)
+        {
+            return (value1 < value2) || AreClose(value1, value2);
+        }
+
         /// <summary>
         /// GreaterThanOrClose - Returns whether or not the first double is greater than or close to
         /// the second double.  That is, whether or not the first is strictly greater than or within
@@ -71,6 +127,18 @@ namespace Avalonia.Utilities
             return (value1 > value2) || AreClose(value1, value2);
         }
 
+        /// <summary>
+        /// GreaterThanOrClose - Returns whether or not the first float is greater than or close to
+        /// the second float.  That is, whether or not the first is strictly greater than or within
+        /// epsilon of the other number.
+        /// </summary>
+        /// <param name="value1"> The first float to compare. </param>
+        /// <param name="value2"> The second float to compare. </param>
+        public static bool GreaterThanOrClose(float value1, float value2)
+        {
+            return (value1 > value2) || AreClose(value1, value2);
+        }
+
         /// <summary>
         /// IsOne - Returns whether or not the double is "close" to 1.  Same as AreClose(double, 1),
         /// but this is faster.
@@ -78,7 +146,17 @@ namespace Avalonia.Utilities
         /// <param name="value"> The double to compare to 1. </param>
         public static bool IsOne(double value)
         {
-            return Math.Abs(value - 1.0) < 10.0 * double.Epsilon;
+            return Math.Abs(value - 1.0) < 10.0 * DoubleEpsilon;
+        }
+
+        /// <summary>
+        /// IsOne - Returns whether or not the float is "close" to 1.  Same as AreClose(float, 1),
+        /// but this is faster.
+        /// </summary>
+        /// <param name="value"> The float to compare to 1. </param>
+        public static bool IsOne(float value)
+        {
+            return Math.Abs(value - 1.0f) < 10.0f * FloatEpsilon;
         }
 
         /// <summary>
@@ -88,7 +166,17 @@ namespace Avalonia.Utilities
         /// <param name="value"> The double to compare to 0. </param>
         public static bool IsZero(double value)
         {
-            return Math.Abs(value) < 10.0 * double.Epsilon;
+            return Math.Abs(value) < 10.0 * DoubleEpsilon;
+        }
+
+        /// <summary>
+        /// IsZero - Returns whether or not the float is "close" to 0.  Same as AreClose(float, 0),
+        /// but this is faster.
+        /// </summary>
+        /// <param name="value"> The float to compare to 0. </param>
+        public static bool IsZero(float value)
+        {
+            return Math.Abs(value) < 10.0f * FloatEpsilon;
         }
 
         /// <summary>

src/Avalonia.Controls/AutoCompleteBox.cs

@@ -468,10 +468,11 @@ namespace Avalonia.Controls
         /// <see cref="P:Avalonia.Controls.AutoCompleteBox.Text" />
         /// dependency property.</value>
         public static readonly DirectProperty<AutoCompleteBox, string> TextProperty =
-            AvaloniaProperty.RegisterDirect<AutoCompleteBox, string>(
-                nameof(Text),
+            TextBlock.TextProperty.AddOwnerWithDataValidation<AutoCompleteBox>(
                 o => o.Text,
-                (o, v) => o.Text = v);
+                (o, v) => o.Text = v,
+                defaultBindingMode: BindingMode.TwoWay,
+                enableDataValidation: true);
 
         /// <summary>
         /// Identifies the
@@ -1244,6 +1245,20 @@ namespace Avalonia.Controls
 
             base.OnApplyTemplate(e);
         }
+        
+        /// <summary>
+        /// Called to update the validation state for properties for which data validation is
+        /// enabled.
+        /// </summary>
+        /// <param name="property">The property.</param>
+        /// <param name="value">The new binding value for the property.</param>
+        protected override void UpdateDataValidation<T>(AvaloniaProperty<T> property, BindingValue<T> value)
+        {
+            if (property == TextProperty)
+            {
+                DataValidationErrors.SetError(this, value.Error);
+            }
+        }
 
         /// <summary>
         /// Provides handling for the

src/Avalonia.Controls/Calendar/Calendar.cs

@@ -998,10 +998,10 @@ namespace Avalonia.Controls
 
 
         /// <summary>
-        /// Gets or sets a value indicating whether DatePicker should change its 
+        /// Gets or sets a value indicating whether CalendarDatePicker should change its 
         /// DisplayDate because of a SelectedDate change on its Calendar.
         /// </summary>
-        internal bool DatePickerDisplayDateFlag { get; set; }
+        internal bool CalendarDatePickerDisplayDateFlag { get; set; }
 
         internal CalendarDayButton FindDayButtonFromDay(DateTime day)
         {

src/Avalonia.Controls/Calendar/DatePicker.cs → src/Avalonia.Controls/Calendar/CalendarDatePicker.cs

@@ -16,29 +16,29 @@ namespace Avalonia.Controls
 {
     /// <summary>
     /// Provides data for the
-    /// <see cref="E:Avalonia.Controls.DatePicker.DateValidationError" />
+    /// <see cref="E:Avalonia.Controls.CalendarDatePicker.DateValidationError" />
     /// event.
     /// </summary>
-    public class DatePickerDateValidationErrorEventArgs : EventArgs
+    public class CalendarDatePickerDateValidationErrorEventArgs : EventArgs
     {
         private bool _throwException;
 
         /// <summary>
         /// Initializes a new instance of the
-        /// <see cref="T:Avalonia.Controls.DatePickerDateValidationErrorEventArgs" />
+        /// <see cref="T:Avalonia.Controls.CalendarDatePickerDateValidationErrorEventArgs" />
         /// class.
         /// </summary>
         /// <param name="exception">
         /// The initial exception from the
-        /// <see cref="E:Avalonia.Controls.DatePicker.DateValidationError" />
+        /// <see cref="E:Avalonia.Controls.CalendarDatePicker.DateValidationError" />
         /// event.
         /// </param>
         /// <param name="text">
         /// The text that caused the
-        /// <see cref="E:Avalonia.Controls.DatePicker.DateValidationError" />
+        /// <see cref="E:Avalonia.Controls.CalendarDatePicker.DateValidationError" />
         /// event.
         /// </param>
-        public DatePickerDateValidationErrorEventArgs(Exception exception, string text)
+        public CalendarDatePickerDateValidationErrorEventArgs(Exception exception, string text)
         {
             this.Text = text;
             this.Exception = exception;
@@ -46,7 +46,7 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets the initial exception associated with the
-        /// <see cref="E:Avalonia.Controls.DatePicker.DateValidationError" />
+        /// <see cref="E:Avalonia.Controls.CalendarDatePicker.DateValidationError" />
         /// event.
         /// </summary>
         /// <value>
@@ -56,7 +56,7 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets the text that caused the
-        /// <see cref="E:Avalonia.Controls.DatePicker.DateValidationError" />
+        /// <see cref="E:Avalonia.Controls.CalendarDatePicker.DateValidationError" />
         /// event.
         /// </summary>
         /// <value>
@@ -66,7 +66,7 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets or sets a value indicating whether
-        /// <see cref="P:Avalonia.Controls.DatePickerDateValidationErrorEventArgs.Exception" />
+        /// <see cref="P:Avalonia.Controls.CalendarDatePickerDateValidationErrorEventArgs.Exception" />
         /// should be thrown.
         /// </summary>
         /// <value>
@@ -74,7 +74,7 @@ namespace Avalonia.Controls
         /// </value>
         /// <exception cref="T:System.ArgumentException">
         /// If set to true and
-        /// <see cref="P:Avalonia.Controls.DatePickerDateValidationErrorEventArgs.Exception" />
+        /// <see cref="P:Avalonia.Controls.CalendarDatePickerDateValidationErrorEventArgs.Exception" />
         /// is null.
         /// </exception>
         public bool ThrowException
@@ -93,9 +93,9 @@ namespace Avalonia.Controls
 
     /// <summary>
     /// Specifies date formats for a
-    /// <see cref="T:Avalonia.Controls.DatePicker" />.
+    /// <see cref="T:Avalonia.Controls.CalendarDatePicker" />.
     /// </summary>
-    public enum DatePickerFormat
+    public enum CalendarDatePickerFormat
     {
         /// <summary>
         /// Specifies that the date should be displayed using unabbreviated days
@@ -115,7 +115,7 @@ namespace Avalonia.Controls
         Custom = 2
     }
 
-    public class DatePicker : TemplatedControl
+    public class CalendarDatePicker : TemplatedControl
     {
         private const string ElementTextBox = "PART_TextBox";
         private const string ElementButton = "PART_Button";
@@ -154,59 +154,59 @@ namespace Avalonia.Controls
         /// </value>
         public CalendarBlackoutDatesCollection BlackoutDates { get; private set; }
 
-        public static readonly DirectProperty<DatePicker, DateTime> DisplayDateProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, DateTime>(
+        public static readonly DirectProperty<CalendarDatePicker, DateTime> DisplayDateProperty =
+            AvaloniaProperty.RegisterDirect<CalendarDatePicker, DateTime>(
                 nameof(DisplayDate),
                 o => o.DisplayDate,
                 (o, v) => o.DisplayDate = v);
-        public static readonly DirectProperty<DatePicker, DateTime?> DisplayDateStartProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, DateTime?>(
+        public static readonly DirectProperty<CalendarDatePicker, DateTime?> DisplayDateStartProperty =
+            AvaloniaProperty.RegisterDirect<CalendarDatePicker, DateTime?>(
                 nameof(DisplayDateStart),
                 o => o.DisplayDateStart,
                 (o, v) => o.DisplayDateStart = v);
-        public static readonly DirectProperty<DatePicker, DateTime?> DisplayDateEndProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, DateTime?>(
+        public static readonly DirectProperty<CalendarDatePicker, DateTime?> DisplayDateEndProperty =
+            AvaloniaProperty.RegisterDirect<CalendarDatePicker, DateTime?>(
                 nameof(DisplayDateEnd),
                 o => o.DisplayDateEnd,
                 (o, v) => o.DisplayDateEnd = v);
         public static readonly StyledProperty<DayOfWeek> FirstDayOfWeekProperty =
-            AvaloniaProperty.Register<DatePicker, DayOfWeek>(nameof(FirstDayOfWeek));
+            AvaloniaProperty.Register<CalendarDatePicker, DayOfWeek>(nameof(FirstDayOfWeek));
 
-        public static readonly DirectProperty<DatePicker, bool> IsDropDownOpenProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, bool>(
+        public static readonly DirectProperty<CalendarDatePicker, bool> IsDropDownOpenProperty =
+            AvaloniaProperty.RegisterDirect<CalendarDatePicker, bool>(
                 nameof(IsDropDownOpen),
                 o => o.IsDropDownOpen,
                 (o, v) => o.IsDropDownOpen = v);
 
         public static readonly StyledProperty<bool> IsTodayHighlightedProperty =
-            AvaloniaProperty.Register<DatePicker, bool>(nameof(IsTodayHighlighted));
-        public static readonly DirectProperty<DatePicker, DateTime?> SelectedDateProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, DateTime?>(
+            AvaloniaProperty.Register<CalendarDatePicker, bool>(nameof(IsTodayHighlighted));
+        public static readonly DirectProperty<CalendarDatePicker, DateTime?> SelectedDateProperty =
+            AvaloniaProperty.RegisterDirect<CalendarDatePicker, DateTime?>(
                 nameof(SelectedDate),
                 o => o.SelectedDate,
                 (o, v) => o.SelectedDate = v);
 
-        public static readonly StyledProperty<DatePickerFormat> SelectedDateFormatProperty =
-            AvaloniaProperty.Register<DatePicker, DatePickerFormat>(
+        public static readonly StyledProperty<CalendarDatePickerFormat> SelectedDateFormatProperty =
+            AvaloniaProperty.Register<CalendarDatePicker, CalendarDatePickerFormat>(
                 nameof(SelectedDateFormat),
-                defaultValue: DatePickerFormat.Short,
+                defaultValue: CalendarDatePickerFormat.Short,
                 validate: IsValidSelectedDateFormat);
 
         public static readonly StyledProperty<string> CustomDateFormatStringProperty =
-            AvaloniaProperty.Register<DatePicker, string>(
+            AvaloniaProperty.Register<CalendarDatePicker, string>(
                 nameof(CustomDateFormatString),
                 defaultValue: "d",
                 validate: IsValidDateFormatString);
 
-        public static readonly DirectProperty<DatePicker, string> TextProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, string>(
+        public static readonly DirectProperty<CalendarDatePicker, string> TextProperty =
+            AvaloniaProperty.RegisterDirect<CalendarDatePicker, string>(
                 nameof(Text),
                 o => o.Text,
                 (o, v) => o.Text = v);
         public static readonly StyledProperty<string> WatermarkProperty =
-            TextBox.WatermarkProperty.AddOwner<DatePicker>();
+            TextBox.WatermarkProperty.AddOwner<CalendarDatePicker>();
         public static readonly StyledProperty<bool> UseFloatingWatermarkProperty =
-            TextBox.UseFloatingWatermarkProperty.AddOwner<DatePicker>();
+            TextBox.UseFloatingWatermarkProperty.AddOwner<CalendarDatePicker>();
 
 
         /// <summary>
@@ -218,9 +218,9 @@ namespace Avalonia.Controls
         /// </value>
         /// <exception cref="T:System.ArgumentOutOfRangeException">
         /// The specified date is not in the range defined by
-        /// <see cref="P:Avalonia.Controls.DatePicker.DisplayDateStart" />
+        /// <see cref="P:Avalonia.Controls.CalendarDatePicker.DisplayDateStart" />
         /// and
-        /// <see cref="P:Avalonia.Controls.DatePicker.DisplayDateEnd" />.
+        /// <see cref="P:Avalonia.Controls.CalendarDatePicker.DisplayDateEnd" />.
         /// </exception>
         public DateTime DisplayDate
         {
@@ -320,7 +320,7 @@ namespace Avalonia.Controls
         /// <exception cref="T:System.ArgumentOutOfRangeException">
         /// An specified format is not valid.
         /// </exception>
-        public DatePickerFormat SelectedDateFormat
+        public CalendarDatePickerFormat SelectedDateFormat
         {
             get { return GetValue(SelectedDateFormatProperty); }
             set { SetValue(SelectedDateFormatProperty, value); }
@@ -380,33 +380,33 @@ namespace Avalonia.Controls
         /// Occurs when <see cref="P:Avalonia.Controls.DatePicker.Text" />
         /// is assigned a value that cannot be interpreted as a date.
         /// </summary>
-        public event EventHandler<DatePickerDateValidationErrorEventArgs> DateValidationError;
+        public event EventHandler<CalendarDatePickerDateValidationErrorEventArgs> DateValidationError;
 
         /// <summary>
         /// Occurs when the
-        /// <see cref="P:Avalonia.Controls.DatePicker.SelectedDate" />
+        /// <see cref="P:Avalonia.Controls.CalendarDatePicker.SelectedDate" />
         /// property is changed.
         /// </summary>
         public event EventHandler<SelectionChangedEventArgs> SelectedDateChanged;
 
-        static DatePicker()
+        static CalendarDatePicker()
         {
-            FocusableProperty.OverrideDefaultValue<DatePicker>(true);
-
-            DisplayDateProperty.Changed.AddClassHandler<DatePicker>((x,e) => x.OnDisplayDateChanged(e));
-            DisplayDateStartProperty.Changed.AddClassHandler<DatePicker>((x,e) => x.OnDisplayDateStartChanged(e));
-            DisplayDateEndProperty.Changed.AddClassHandler<DatePicker>((x,e) => x.OnDisplayDateEndChanged(e));
-            IsDropDownOpenProperty.Changed.AddClassHandler<DatePicker>((x,e) => x.OnIsDropDownOpenChanged(e));
-            SelectedDateProperty.Changed.AddClassHandler<DatePicker>((x,e) => x.OnSelectedDateChanged(e));
-            SelectedDateFormatProperty.Changed.AddClassHandler<DatePicker>((x,e) => x.OnSelectedDateFormatChanged(e));
-            CustomDateFormatStringProperty.Changed.AddClassHandler<DatePicker>((x,e) => x.OnCustomDateFormatStringChanged(e));
-            TextProperty.Changed.AddClassHandler<DatePicker>((x,e) => x.OnTextChanged(e));
+            FocusableProperty.OverrideDefaultValue<CalendarDatePicker>(true);
+
+            DisplayDateProperty.Changed.AddClassHandler<CalendarDatePicker>((x,e) => x.OnDisplayDateChanged(e));
+            DisplayDateStartProperty.Changed.AddClassHandler<CalendarDatePicker>((x,e) => x.OnDisplayDateStartChanged(e));
+            DisplayDateEndProperty.Changed.AddClassHandler<CalendarDatePicker>((x,e) => x.OnDisplayDateEndChanged(e));
+            IsDropDownOpenProperty.Changed.AddClassHandler<CalendarDatePicker>((x,e) => x.OnIsDropDownOpenChanged(e));
+            SelectedDateProperty.Changed.AddClassHandler<CalendarDatePicker>((x,e) => x.OnSelectedDateChanged(e));
+            SelectedDateFormatProperty.Changed.AddClassHandler<CalendarDatePicker>((x,e) => x.OnSelectedDateFormatChanged(e));
+            CustomDateFormatStringProperty.Changed.AddClassHandler<CalendarDatePicker>((x,e) => x.OnCustomDateFormatStringChanged(e));
+            TextProperty.Changed.AddClassHandler<CalendarDatePicker>((x,e) => x.OnTextChanged(e));
         }
         /// <summary>
         /// Initializes a new instance of the
         /// <see cref="T:Avalonia.Controls.DatePicker" /> class.
         /// </summary>
-        public DatePicker()
+        public CalendarDatePicker()
         {
             FirstDayOfWeek = DateTimeHelper.GetCurrentDateFormat().FirstDayOfWeek;
             _defaultText = string.Empty;
@@ -662,12 +662,12 @@ namespace Avalonia.Controls
                 // change is coming from the Calendar UI itself, so, we
                 // shouldn't change the DisplayDate since it will automatically
                 // be changed by the Calendar
-                if ((day.Month != DisplayDate.Month || day.Year != DisplayDate.Year) && (_calendar == null || !_calendar.DatePickerDisplayDateFlag))
+                if ((day.Month != DisplayDate.Month || day.Year != DisplayDate.Year) && (_calendar == null || !_calendar.CalendarDatePickerDisplayDateFlag))
                 {
                     DisplayDate = day;
                 }
                 if(_calendar != null)
-                    _calendar.DatePickerDisplayDateFlag = false;
+                    _calendar.CalendarDatePickerDisplayDateFlag = false;
             }
             else
             {
@@ -707,7 +707,7 @@ namespace Avalonia.Controls
         }
         private void OnCustomDateFormatStringChanged(AvaloniaPropertyChangedEventArgs e)
         {
-            if(SelectedDateFormat == DatePickerFormat.Custom)
+            if(SelectedDateFormat == CalendarDatePickerFormat.Custom)
             {
                 OnDateFormatChanged();
             }
@@ -752,15 +752,15 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Raises the
-        /// <see cref="E:Avalonia.Controls.DatePicker.DateValidationError" />
+        /// <see cref="E:Avalonia.Controls.CalendarDatePicker.DateValidationError" />
         /// event.
         /// </summary>
         /// <param name="e">
         /// A
-        /// <see cref="T:Avalonia.Controls.DatePickerDateValidationErrorEventArgs" />
+        /// <see cref="T:Avalonia.Controls.CalendarDatePickerDateValidationErrorEventArgs" />
         /// that contains the event data.
         /// </param>
-        protected virtual void OnDateValidationError(DatePickerDateValidationErrorEventArgs e)
+        protected virtual void OnDateValidationError(CalendarDatePickerDateValidationErrorEventArgs e)
         {
             DateValidationError?.Invoke(this, e);
         }
@@ -959,7 +959,7 @@ namespace Avalonia.Controls
                 }
                 else
                 {
-                    var dateValidationError = new DatePickerDateValidationErrorEventArgs(new ArgumentOutOfRangeException(nameof(text), "SelectedDate value is not valid."), text);
+                    var dateValidationError = new CalendarDatePickerDateValidationErrorEventArgs(new ArgumentOutOfRangeException(nameof(text), "SelectedDate value is not valid."), text);
                     OnDateValidationError(dateValidationError);
 
                     if (dateValidationError.ThrowException)
@@ -970,7 +970,7 @@ namespace Avalonia.Controls
             }
             catch (FormatException ex)
             {
-                DatePickerDateValidationErrorEventArgs textParseError = new DatePickerDateValidationErrorEventArgs(ex, text);
+                CalendarDatePickerDateValidationErrorEventArgs textParseError = new CalendarDatePickerDateValidationErrorEventArgs(ex, text);
                 OnDateValidationError(textParseError);
 
                 if (textParseError.ThrowException)
@@ -986,11 +986,11 @@ namespace Avalonia.Controls
 
             switch (SelectedDateFormat)
             {
-                case DatePickerFormat.Short:
+                case CalendarDatePickerFormat.Short:
                     return string.Format(CultureInfo.CurrentCulture, d.ToString(dtfi.ShortDatePattern, dtfi));
-                case DatePickerFormat.Long:
+                case CalendarDatePickerFormat.Long:
                     return string.Format(CultureInfo.CurrentCulture, d.ToString(dtfi.LongDatePattern, dtfi));
-                case DatePickerFormat.Custom:
+                case CalendarDatePickerFormat.Custom:
                     return string.Format(CultureInfo.CurrentCulture, d.ToString(CustomDateFormatString, dtfi));
             }
             return null;
@@ -1118,12 +1118,12 @@ namespace Avalonia.Controls
 
                     switch (SelectedDateFormat)
                     {
-                        case DatePickerFormat.Long:
+                        case CalendarDatePickerFormat.Long:
                             {
                                 watermarkText = string.Format(CultureInfo.CurrentCulture, watermarkFormat, dtfi.LongDatePattern.ToString());
                                 break;
                             }
-                        case DatePickerFormat.Short:
+                        case CalendarDatePickerFormat.Short:
                         default:
                             {
                                 watermarkText = string.Format(CultureInfo.CurrentCulture, watermarkFormat, dtfi.ShortDatePattern.ToString());
@@ -1139,11 +1139,11 @@ namespace Avalonia.Controls
             }
         }
 
-        private static bool IsValidSelectedDateFormat(DatePickerFormat value)
+        private static bool IsValidSelectedDateFormat(CalendarDatePickerFormat value)
         {
-            return value == DatePickerFormat.Long
-                || value == DatePickerFormat.Short
-                || value == DatePickerFormat.Custom;
+            return value == CalendarDatePickerFormat.Long
+                || value == CalendarDatePickerFormat.Short
+                || value == CalendarDatePickerFormat.Custom;
         }
         private static bool IsValidDateFormatString(string formatString)
         {

src/Avalonia.Controls/Calendar/CalendarItem.cs

@@ -909,7 +909,7 @@ namespace Avalonia.Controls.Primitives
                         case CalendarSelectionMode.SingleDate:
                             {
                                 DateTime selectedDate = (DateTime)b.DataContext;
-                                Owner.DatePickerDisplayDateFlag = true;
+                                Owner.CalendarDatePickerDisplayDateFlag = true;
                                 if (Owner.SelectedDates.Count == 0)
                                 {
                                     Owner.SelectedDates.Add(selectedDate);
@@ -981,7 +981,7 @@ namespace Avalonia.Controls.Primitives
                                 }
                             case CalendarSelectionMode.SingleDate:
                                 {
-                                    Owner.DatePickerDisplayDateFlag = true;
+                                    Owner.CalendarDatePickerDisplayDateFlag = true;
                                     if (Owner.SelectedDates.Count == 0)
                                     {
                                         Owner.SelectedDates.Add(selectedDate);

src/Avalonia.Controls/Grid.cs

@@ -1228,7 +1228,7 @@ namespace Avalonia.Controls
             Debug.Assert(1 < count && 0 <= start && (start + count) <= definitions.Count);
 
             //  avoid processing when asked to distribute "0"
-            if (!_IsZero(requestedSize))
+            if (!MathUtilities.IsZero(requestedSize))
             {
                 DefinitionBase[] tempDefinitions = TempDefinitions; //  temp array used to remember definitions for sorting
                 int end = start + count;
@@ -1306,7 +1306,7 @@ namespace Avalonia.Controls
                         }
 
                         //  sanity check: requested size must all be distributed
-                        Debug.Assert(_IsZero(sizeToDistribute));
+                        Debug.Assert(MathUtilities.IsZero(sizeToDistribute));
                     }
                     else if (requestedSize <= rangeMaxSize)
                     {
@@ -1346,7 +1346,7 @@ namespace Avalonia.Controls
                         }
 
                         //  sanity check: requested size must all be distributed
-                        Debug.Assert(_IsZero(sizeToDistribute));
+                        Debug.Assert(MathUtilities.IsZero(sizeToDistribute));
                     }
                     else
                     {
@@ -1358,7 +1358,7 @@ namespace Avalonia.Controls
                         double equalSize = requestedSize / count;
 
                         if (equalSize < maxMaxSize
-                            && !_AreClose(equalSize, maxMaxSize))
+                            && !MathUtilities.AreClose(equalSize, maxMaxSize))
                         {
                             //  equi-size is less than maximum of maxSizes.
                             //  in this case distribute so that smaller definitions grow faster than
@@ -2151,7 +2151,7 @@ namespace Avalonia.Controls
                 // and precision of floating-point computation.  (However, the resulting
                 // display is subject to anti-aliasing problems.   TANSTAAFL.)
 
-                if (!_AreClose(roundedTakenSize, finalSize))
+                if (!MathUtilities.AreClose(roundedTakenSize, finalSize))
                 {
                     // Compute deltas
                     for (int i = 0; i < definitions.Count; ++i)
@@ -2168,7 +2168,7 @@ namespace Avalonia.Controls
                     if (roundedTakenSize > finalSize)
                     {
                         int i = definitions.Count - 1;
-                        while ((adjustedSize > finalSize && !_AreClose(adjustedSize, finalSize)) && i >= 0)
+                        while ((adjustedSize > finalSize && !MathUtilities.AreClose(adjustedSize, finalSize)) && i >= 0)
                         {
                             DefinitionBase definition = definitions[definitionIndices[i]];
                             double final = definition.SizeCache - dpiIncrement;
@@ -2184,7 +2184,7 @@ namespace Avalonia.Controls
                     else if (roundedTakenSize < finalSize)
                     {
                         int i = 0;
-                        while ((adjustedSize < finalSize && !_AreClose(adjustedSize, finalSize)) && i < definitions.Count)
+                        while ((adjustedSize < finalSize && !MathUtilities.AreClose(adjustedSize, finalSize)) && i < definitions.Count)
                         {
                             DefinitionBase definition = definitions[definitionIndices[i]];
                             double final = definition.SizeCache + dpiIncrement;
@@ -2595,27 +2595,6 @@ namespace Avalonia.Controls
             set { SetFlags(value, Flags.HasGroup3CellsInAutoRows); }
         }
 
-        /// <summary>
-        /// fp version of <c>d == 0</c>.
-        /// </summary>
-        /// <param name="d">Value to check.</param>
-        /// <returns><c>true</c> if d == 0.</returns>
-        private static bool _IsZero(double d)
-        {
-            return (Math.Abs(d) < double.Epsilon);
-        }
-
-        /// <summary>
-        /// fp version of <c>d1 == d2</c>
-        /// </summary>
-        /// <param name="d1">First value to compare</param>
-        /// <param name="d2">Second value to compare</param>
-        /// <returns><c>true</c> if d1 == d2</returns>
-        private static bool _AreClose(double d1, double d2)
-        {
-            return (Math.Abs(d1 - d2) < double.Epsilon);
-        }
-
         /// <summary>
         /// Returns reference to extended data bag.
         /// </summary>

src/Avalonia.Controls/IndexPath.cs

@@ -123,6 +123,26 @@ namespace Avalonia.Controls
             }
         }
 
+        public bool IsAncestorOf(in IndexPath other)
+        {
+            if (other.GetSize() <= GetSize())
+            {
+                return false;
+            }
+
+            var size = GetSize();
+
+            for (int i = 0; i < size; i++)
+            {
+                if (GetAt(i) != other.GetAt(i))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
         public override string ToString()
         {
             if (_path != null)

src/Avalonia.Controls/IndexRange.cs

@@ -132,6 +132,53 @@ namespace Avalonia.Controls
             return result;
         }
 
+        public static int Intersect(
+            IList<IndexRange> ranges,
+            IndexRange range,
+            IList<IndexRange>? removed = null)
+        {
+            var result = 0;
+
+            for (var i = 0; i < ranges.Count && range != s_invalid; ++i)
+            {
+                var existing = ranges[i];
+
+                if (existing.End < range.Begin || existing.Begin > range.End)
+                {
+                    removed?.Add(existing);
+                    ranges.RemoveAt(i--);
+                    result += existing.Count;
+                }
+                else
+                {
+                    if (existing.Begin < range.Begin)
+                    {
+                        var except = new IndexRange(existing.Begin, range.Begin - 1);
+                        removed?.Add(except);
+                        ranges[i] = existing = new IndexRange(range.Begin, existing.End);
+                        result += except.Count;
+                    }
+
+                    if (existing.End > range.End)
+                    {
+                        var except = new IndexRange(range.End + 1, existing.End);
+                        removed?.Add(except);
+                        ranges[i] = new IndexRange(existing.Begin, range.End);
+                        result += except.Count;
+                    }
+                }
+            }
+
+            MergeRanges(ranges);
+
+            if (removed is object)
+            {
+                MergeRanges(removed);
+            }
+
+            return result;
+        }
+
         public static int Remove(
             IList<IndexRange> ranges,
             IndexRange range,

src/Avalonia.Controls/SelectionModel.cs

@@ -46,17 +46,25 @@ namespace Avalonia.Controls
 
                     if (_rootNode.Source != null)
                     {
-                        if (_rootNode.Source != null)
+                        // Temporarily prevent auto-select when switching source.
+                        var restoreAutoSelect = _autoSelect;
+                        _autoSelect = false;
+
+                        try
                         {
                             using (var operation = new Operation(this))
                             {
                                 ClearSelection(resetAnchor: true);
                             }
                         }
+                        finally
+                        {
+                            _autoSelect = restoreAutoSelect;
+                        }
                     }
 
                     _rootNode.Source = value;
-                    ApplyAutoSelect();
+                    ApplyAutoSelect(true);
 
                     RaisePropertyChanged("Source");
 
@@ -114,7 +122,7 @@ namespace Avalonia.Controls
                 if (_autoSelect != value)
                 {
                     _autoSelect = value;
-                    ApplyAutoSelect();
+                    ApplyAutoSelect(true);
                 }
             }
         }
@@ -133,7 +141,7 @@ namespace Avalonia.Controls
                     while (current?.AnchorIndex >= 0)
                     {
                         path.Add(current.AnchorIndex);
-                        current = current.GetAt(current.AnchorIndex, false);
+                        current = current.GetAt(current.AnchorIndex, false, default);
                     }
 
                     anchor = new IndexPath(path);
@@ -188,7 +196,6 @@ namespace Avalonia.Controls
                     using var operation = new Operation(this);
                     ClearSelection(resetAnchor: true);
                     SelectWithPathImpl(value, select: true);
-                    ApplyAutoSelect();
                 }
             }
         }
@@ -384,21 +391,18 @@ namespace Avalonia.Controls
         {
             using var operation = new Operation(this);
             SelectImpl(index, select: false);
-            ApplyAutoSelect();
         }
 
         public void Deselect(int groupIndex, int itemIndex)
         {
             using var operation = new Operation(this);
             SelectWithGroupImpl(groupIndex, itemIndex, select: false);
-            ApplyAutoSelect();
         }
 
         public void DeselectAt(IndexPath index)
         {
             using var operation = new Operation(this);
             SelectWithPathImpl(index, select: false);
-            ApplyAutoSelect();
         }
 
         public bool IsSelected(int index) => _rootNode.IsSelected(index);
@@ -416,7 +420,7 @@ namespace Avalonia.Controls
             for (int i = 0; i < path.GetSize() - 1; i++)
             {
                 var childIndex = path.GetAt(i);
-                node = node.GetAt(childIndex, realizeChild: false);
+                node = node.GetAt(childIndex, false, default);
 
                 if (node == null)
                 {
@@ -451,7 +455,7 @@ namespace Avalonia.Controls
             }
 
             var isSelected = (bool?)false;
-            var childNode = _rootNode.GetAt(groupIndex, realizeChild: false);
+            var childNode = _rootNode.GetAt(groupIndex, false, default);
 
             if (childNode != null)
             {
@@ -470,7 +474,7 @@ namespace Avalonia.Controls
             for (int i = 0; i < path.GetSize() - 1; i++)
             {
                 var childIndex = path.GetAt(i);
-                node = node.GetAt(childIndex, realizeChild: false);
+                node = node.GetAt(childIndex, false, default);
 
                 if (node == null)
                 {
@@ -565,7 +569,6 @@ namespace Avalonia.Controls
         {
             using var operation = new Operation(this);
             ClearSelection(resetAnchor: true);
-            ApplyAutoSelect();
         }
 
         public IDisposable Update() => new Operation(this);
@@ -592,10 +595,13 @@ namespace Avalonia.Controls
             }
 
             OnSelectionChanged(e);
-            ApplyAutoSelect();
+            ApplyAutoSelect(true);
         }
 
-        internal IObservable<object?>? ResolvePath(object data, IndexPath dataIndexPath)
+        internal IObservable<object?>? ResolvePath(
+            object data,
+            IndexPath dataIndexPath,
+            IndexPath finalIndexPath)
         {
             IObservable<object?>? resolved = null;
 
@@ -604,18 +610,22 @@ namespace Avalonia.Controls
             {
                 if (_childrenRequestedEventArgs == null)
                 {
-                    _childrenRequestedEventArgs = new SelectionModelChildrenRequestedEventArgs(data, dataIndexPath, false);
+                    _childrenRequestedEventArgs = new SelectionModelChildrenRequestedEventArgs(
+                        data,
+                        dataIndexPath,
+                        finalIndexPath,
+                        false);
                 }
                 else
                 {
-                    _childrenRequestedEventArgs.Initialize(data, dataIndexPath, false);
+                    _childrenRequestedEventArgs.Initialize(data, dataIndexPath, finalIndexPath, false);
                 }
 
                 ChildrenRequested(this, _childrenRequestedEventArgs);
                 resolved = _childrenRequestedEventArgs.Children;
 
                 // Clear out the values in the args so that it cannot be used after the event handler call.
-                _childrenRequestedEventArgs.Initialize(null, default, true);
+                _childrenRequestedEventArgs.Initialize(null, default, default, true);
             }
 
             return resolved;
@@ -632,6 +642,8 @@ namespace Avalonia.Controls
             {
                 AnchorIndex = default;
             }
+
+            OnSelectionChanged();
         }
 
         private void OnSelectionChanged(SelectionModelSelectionChangedEventArgs? e = null)
@@ -667,6 +679,8 @@ namespace Avalonia.Controls
             {
                 AnchorIndex = new IndexPath(index);
             }
+
+            OnSelectionChanged();
         }
 
         private void SelectWithGroupImpl(int groupIndex, int itemIndex, bool select)
@@ -676,13 +690,15 @@ namespace Avalonia.Controls
                 ClearSelection(resetAnchor: true);
             }
 
-            var childNode = _rootNode.GetAt(groupIndex, realizeChild: true);
+            var childNode = _rootNode.GetAt(groupIndex, true, new IndexPath(groupIndex, itemIndex));
             var selected = childNode!.Select(itemIndex, select);
 
             if (selected)
             {
                 AnchorIndex = new IndexPath(groupIndex, itemIndex);
             }
+
+            OnSelectionChanged();
         }
 
         private void SelectWithPathImpl(IndexPath index, bool select)
@@ -711,6 +727,8 @@ namespace Avalonia.Controls
             {
                 AnchorIndex = index;
             }
+
+            OnSelectionChanged();
         }
 
         private void SelectRangeFromAnchorImpl(int index, bool select)
@@ -724,6 +742,7 @@ namespace Avalonia.Controls
             }
 
             _rootNode.SelectRange(new IndexRange(anchorIndex, index), select);
+            OnSelectionChanged();
         }
 
         private void SelectRangeFromAnchorWithGroupImpl(int endGroupIndex, int endItemIndex, bool select)
@@ -752,11 +771,13 @@ namespace Avalonia.Controls
 
             for (int groupIdx = startGroupIndex; groupIdx <= endGroupIndex; groupIdx++)
             {
-                var groupNode = _rootNode.GetAt(groupIdx, realizeChild: true)!;
+                var groupNode = _rootNode.GetAt(groupIdx, true, new IndexPath(endGroupIndex, endItemIndex))!;
                 int startIndex = groupIdx == startGroupIndex ? startItemIndex : 0;
                 int endIndex = groupIdx == endGroupIndex ? endItemIndex : groupNode.DataCount - 1;
                 groupNode.SelectRange(new IndexRange(startIndex, endIndex), select);
             }
+
+            OnSelectionChanged();
         }
 
         private void SelectRangeImpl(IndexPath start, IndexPath end, bool select)
@@ -784,6 +805,8 @@ namespace Avalonia.Controls
                         info.ParentNode!.Select(info.Path.GetAt(info.Path.GetSize() - 1), select);
                     }
                 });
+
+            OnSelectionChanged();
         }
 
         private void BeginOperation()
@@ -806,6 +829,8 @@ namespace Avalonia.Controls
 
             if (--_operationCount == 0)
             {
+                ApplyAutoSelect(false);
+
                 var changes = new List<SelectionNodeOperation>();
                 _rootNode.EndOperation(changes);
 
@@ -827,7 +852,7 @@ namespace Avalonia.Controls
             }
         }
 
-        private void ApplyAutoSelect()
+        private void ApplyAutoSelect(bool createOperation)
         {
             if (AutoSelect)
             {
@@ -835,8 +860,15 @@ namespace Avalonia.Controls
 
                 if (SelectedIndex == default && _rootNode.ItemsSourceView?.Count > 0)
                 {
-                    using var operation = new Operation(this);
-                    SelectImpl(0, true);
+                    if (createOperation)
+                    {
+                        using var operation = new Operation(this);
+                        SelectImpl(0, true);
+                    }
+                    else
+                    {
+                        SelectImpl(0, true);
+                    }
                 }
             }
         }

src/Avalonia.Controls/SelectionModelChangeSet.cs

@@ -135,7 +135,7 @@ namespace Avalonia.Controls
                 if (index >= currentIndex && index < currentIndex + currentCount)
                 {
                     int targetIndex = GetIndexAt(getRanges(info), index - currentIndex);
-                    item = info.Items?.GetAt(targetIndex);
+                    item = info.Items?.Count > targetIndex ? info.Items?.GetAt(targetIndex) : null;
                     break;
                 }
 

src/Avalonia.Controls/SelectionModelChildrenRequestedEventArgs.cs

@@ -16,15 +16,17 @@ namespace Avalonia.Controls
     {
         private object? _source;
         private IndexPath _sourceIndexPath;
+        private IndexPath _finalIndexPath;
         private bool _throwOnAccess;
         
         internal SelectionModelChildrenRequestedEventArgs(
             object source,
             IndexPath sourceIndexPath,
+            IndexPath finalIndexPath,
             bool throwOnAccess)
         {
             source = source ?? throw new ArgumentNullException(nameof(source));
-            Initialize(source, sourceIndexPath, throwOnAccess);
+            Initialize(source, sourceIndexPath, finalIndexPath, throwOnAccess);
         }
 
         /// <summary>
@@ -65,9 +67,26 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <summary>
+        /// Gets the index of the final object which is being attempted to be retrieved.
+        /// </summary>
+        public IndexPath FinalIndex
+        {
+            get
+            {
+                if (_throwOnAccess)
+                {
+                    throw new ObjectDisposedException(nameof(SelectionModelChildrenRequestedEventArgs));
+                }
+
+                return _finalIndexPath;
+            }
+        }
+
         internal void Initialize(
             object? source,
             IndexPath sourceIndexPath,
+            IndexPath finalIndexPath,
             bool throwOnAccess)
         {
             if (!throwOnAccess && source == null)
@@ -77,6 +96,7 @@ namespace Avalonia.Controls
 
             _source = source;
             _sourceIndexPath = sourceIndexPath;
+            _finalIndexPath = finalIndexPath;
             _throwOnAccess = throwOnAccess;
         }
     }

src/Avalonia.Controls/SelectionNode.cs

@@ -101,6 +101,7 @@ namespace Avalonia.Controls
 
                     ItemsSourceView = newDataSource;
 
+                    TrimInvalidSelections();
                     PopulateSelectedItemsFromSelectedIndices();
                     HookupCollectionChangedHandler();
                     OnSelectionChanged();
@@ -108,6 +109,26 @@ namespace Avalonia.Controls
             }
         }
 
+        private void TrimInvalidSelections()
+        {
+            if (_selected == null || ItemsSourceView == null)
+            {
+                return;
+            }
+
+            var validRange = ItemsSourceView.Count > 0 ? new IndexRange(0, ItemsSourceView.Count - 1) : new IndexRange(-1, -1);
+            var removed = new List<IndexRange>();
+            var removedCount = IndexRange.Intersect(_selected, validRange, removed);
+
+            if (removedCount > 0)
+            {
+                using var operation = _manager.Update();
+                SelectedCount -= removedCount;
+                OnSelectionChanged();
+                _operation!.Deselected(removed);
+            }
+        }
+
         public ItemsSourceView? ItemsSourceView { get; private set; }
         public int DataCount => ItemsSourceView?.Count ?? 0;
         public int ChildrenNodeCount => _childrenNodes.Count;
@@ -141,7 +162,7 @@ namespace Avalonia.Controls
         // create a bunch of leaf node instances - instead i use the same instance m_leafNode to avoid 
         // an explosion of node objects. However, I'm still creating the m_childrenNodes 
         // collection unfortunately.
-        public SelectionNode? GetAt(int index, bool realizeChild)
+        public SelectionNode? GetAt(int index, bool realizeChild, IndexPath finalIndexPath)
         {
             SelectionNode? child = null;
             
@@ -171,7 +192,7 @@ namespace Avalonia.Controls
                     if (childData != null)
                     {
                         var childDataIndexPath = IndexPath.CloneWithChildIndex(index);
-                        resolver = _manager.ResolvePath(childData, childDataIndexPath);
+                        resolver = _manager.ResolvePath(childData, childDataIndexPath, finalIndexPath);
                     }
 
                     if (resolver != null)
@@ -843,7 +864,7 @@ namespace Avalonia.Controls
                     int notSelectedCount = 0;
                     for (int i = 0; i < ChildrenNodeCount; i++)
                     {
-                        var child = GetAt(i, realizeChild: false);
+                        var child = GetAt(i, false, default);
 
                         if (child != null)
                         {

src/Avalonia.Controls/Slider.cs

@@ -193,7 +193,8 @@ namespace Avalonia.Controls
             var orient = Orientation == Orientation.Horizontal;
 
             var pointDen = orient ? _track.Bounds.Width : _track.Bounds.Height;
-            pointDen += double.Epsilon; // Just add epsilon to avoid divide by zero exceptions.
+            // Just add epsilon to avoid NaN in case 0/0
+            pointDen += double.Epsilon;
 
             var pointNum = orient ? x.Position.X : x.Position.Y;
             var logicalPos = MathUtilities.Clamp(pointNum / pointDen, 0.0d, 1.0d);

src/Avalonia.Controls/TreeView.cs

@@ -119,9 +119,10 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets or sets the selected item.
         /// </summary>
-        /// <summary>
-        /// Gets or sets the selected item.
-        /// </summary>
+        /// <remarks>
+        /// Note that setting this property only currently works if the item is expanded to be visible.
+        /// To select non-expanded nodes use `Selection.SelectedIndex`.
+        /// </remarks>
         public object SelectedItem
         {
             get => Selection.SelectedItem;
@@ -346,7 +347,7 @@ namespace Avalonia.Controls
 
                 if (container != null)
                 {
-                    container.BringIntoView();
+                    DispatcherTimer.RunOnce(container.BringIntoView, TimeSpan.Zero);
                 }
             }
         }
@@ -395,10 +396,17 @@ namespace Avalonia.Controls
 
         private void OnSelectionModelChildrenRequested(object sender, SelectionModelChildrenRequestedEventArgs e)
         {
-            var container = ItemContainerGenerator.Index.ContainerFromItem(e.Source) as ItemsControl;
+            var container = ItemContainerGenerator.Index.ContainerFromItem(e.Source) as TreeViewItem;
 
             if (container is object)
             {
+                if (e.SourceIndex.IsAncestorOf(e.FinalIndex))
+                {
+                    container.IsExpanded = true;
+                    container.ApplyTemplate();
+                    container.Presenter?.ApplyTemplate();
+                }
+
                 e.Children = Observable.CombineLatest(
                     container.GetObservable(TreeViewItem.IsExpandedProperty),
                     container.GetObservable(ItemsProperty),

src/Avalonia.Controls/Utils/BorderRenderHelper.cs

@@ -1,6 +1,7 @@
 using System;
 using Avalonia.Media;
 using Avalonia.Platform;
+using Avalonia.Utilities;
 
 namespace Avalonia.Controls.Utils
 {
@@ -119,7 +120,7 @@ namespace Avalonia.Controls.Utils
                 }
 
                 var rect = new Rect(_size);
-                if (Math.Abs(borderThickness) > double.Epsilon)
+                if (!MathUtilities.IsZero(borderThickness))
                     rect = rect.Deflate(borderThickness * 0.5);
                 var rrect = new RoundedRect(rect, _cornerRadius.TopLeft, _cornerRadius.TopRight,
                     _cornerRadius.BottomRight, _cornerRadius.BottomLeft);

src/Avalonia.Controls/Utils/SelectionTreeHelper.cs

@@ -28,7 +28,7 @@ namespace Avalonia.Controls.Utils
 
                 if (depth < path.GetSize() - 1)
                 {
-                    node = node.GetAt(childIndex, realizeChildren)!;
+                    node = node.GetAt(childIndex, realizeChildren, path)!;
                 }
             }
         }
@@ -50,7 +50,7 @@ namespace Avalonia.Controls.Utils
                 int count = realizeChildren ? nextNode.Node.DataCount : nextNode.Node.ChildrenNodeCount;
                 for (int i = count - 1; i >= 0; i--)
                 {
-                    var child = nextNode.Node.GetAt(i, realizeChildren);
+                    var child = nextNode.Node.GetAt(i, realizeChildren, nextNode.Path);
                     var childPath = nextNode.Path.CloneWithChildIndex(i);
                     if (child != null)
                     {
@@ -90,7 +90,7 @@ namespace Avalonia.Controls.Utils
 
                     for (int i = endIndex; i >= startIndex; i--)
                     {
-                        var child = node.GetAt(i, realizeChild: true);
+                        var child = node.GetAt(i, true, end);
                         if (child != null)
                         {
                             var childPath = currentPath.CloneWithChildIndex(i);
@@ -112,7 +112,7 @@ namespace Avalonia.Controls.Utils
                 int endIndex = depth < end.GetSize() && isEndPath ? end.GetAt(depth) : info.Node.DataCount - 1;
                 for (int i = endIndex; i >= startIndex; i--)
                 {
-                    var child = info.Node.GetAt(i, realizeChild: true);
+                    var child = info.Node.GetAt(i, true, end);
                     if (child != null)
                     {
                         var childPath = info.Path.CloneWithChildIndex(i);

src/Avalonia.Diagnostics/Diagnostics/ViewModels/MainViewModel.cs

@@ -2,6 +2,7 @@
 using Avalonia.Controls;
 using Avalonia.Diagnostics.Models;
 using Avalonia.Input;
+using Avalonia.Threading;
 
 namespace Avalonia.Diagnostics.ViewModels
 {
@@ -49,7 +50,21 @@ namespace Avalonia.Diagnostics.ViewModels
                     value is TreePageViewModel newTree &&
                     oldTree?.SelectedNode?.Visual is IControl control)
                 {
-                    newTree.SelectControl(control);
+                    // HACK: We want to select the currently selected control in the new tree, but
+                    // to select nested nodes in TreeView, currently the TreeView has to be able to
+                    // expand the parent nodes. Because at this point the TreeView isn't visible,
+                    // this will fail unless we schedule the selection to run after layout.
+                    DispatcherTimer.RunOnce(
+                        () =>
+                        {
+                            try
+                            {
+                                newTree.SelectControl(control);
+                            }
+                            catch { }
+                        },
+                        TimeSpan.FromMilliseconds(0),
+                        DispatcherPriority.ApplicationIdle);
                 }
 
                 RaiseAndSetIfChanged(ref _content, value);

src/Avalonia.Diagnostics/Diagnostics/ViewModels/TreeNode.cs

@@ -1,11 +1,11 @@
 using System;
+using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.Reactive;
 using System.Reactive.Linq;
 using Avalonia.Collections;
 using Avalonia.Controls;
 using Avalonia.LogicalTree;
-using Avalonia.Styling;
 using Avalonia.VisualTree;
 
 namespace Avalonia.Diagnostics.ViewModels
@@ -82,5 +82,41 @@ namespace Avalonia.Diagnostics.ViewModels
             get;
             private set;
         }
+
+        public IndexPath Index
+        {
+            get
+            {
+                var indices = new List<int>();
+                var child = this;
+                var parent = Parent;
+                
+                while (parent is object)
+                {
+                    indices.Add(IndexOf(parent.Children, child));
+                    child = child.Parent;
+                    parent = parent.Parent;
+                }
+
+                indices.Add(0);
+                indices.Reverse();
+                return new IndexPath(indices);
+            }
+        }
+
+        private static int IndexOf(IReadOnlyList<TreeNode> collection, TreeNode item)
+        {
+            var count = collection.Count;
+
+            for (var i = 0; i < count; ++i)
+            {
+                if (collection[i] == item)
+                {
+                    return i;
+                }
+            }
+
+            throw new AvaloniaInternalException("TreeNode was not present in parent Children collection.");
+        }
     }
 }

src/Avalonia.Diagnostics/Diagnostics/ViewModels/TreePageViewModel.cs

@@ -6,28 +6,40 @@ namespace Avalonia.Diagnostics.ViewModels
 {
     internal class TreePageViewModel : ViewModelBase, IDisposable
     {
-        private TreeNode _selected;
+        private TreeNode _selectedNode;
         private ControlDetailsViewModel _details;
         private string _propertyFilter;
 
         public TreePageViewModel(TreeNode[] nodes)
         {
             Nodes = nodes;
-        }
+            Selection = new SelectionModel
+            { 
+                SingleSelect = true,
+                Source = Nodes 
+            };
+
+            Selection.SelectionChanged += (s, e) =>
+            {
+                SelectedNode = (TreeNode)Selection.SelectedItem;
+            };
+       }
 
         public TreeNode[] Nodes { get; protected set; }
 
+        public SelectionModel Selection { get; }
+
         public TreeNode SelectedNode
         {
-            get => _selected;
-            set
+            get => _selectedNode;
+            private set
             {
                 if (Details != null)
                 {
                     _propertyFilter = Details.PropertyFilter;
                 }
 
-                if (RaiseAndSetIfChanged(ref _selected, value))
+                if (RaiseAndSetIfChanged(ref _selectedNode, value))
                 {
                     Details = value != null ?
                         new ControlDetailsViewModel(value.Visual, _propertyFilter) :
@@ -83,8 +95,8 @@ namespace Avalonia.Diagnostics.ViewModels
 
             if (node != null)
             {
-                SelectedNode = node;
                 ExpandNode(node.Parent);
+                Selection.SelectedIndex = node.Index;
             }
         }
 

src/Avalonia.Diagnostics/Diagnostics/Views/TreePageView.xaml

@@ -6,7 +6,7 @@
     <TreeView Name="tree"
               BorderThickness="0"
               Items="{Binding Nodes}"
-              SelectedItem="{Binding SelectedNode, Mode=TwoWay}">
+              Selection="{Binding Selection}">
       <TreeView.DataTemplates>
         <TreeDataTemplate DataType="vm:TreeNode"
                           ItemsSource="{Binding Children}">

src/Avalonia.Themes.Fluent/DatePicker.xaml → src/Avalonia.Themes.Default/CalendarDatePicker.xaml

@@ -8,7 +8,7 @@
 <Styles xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:sys="clr-namespace:System;assembly=netstandard">
-  <Style Selector="DatePicker">
+  <Style Selector="CalendarDatePicker">
 
     <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}"/>
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}"/>
@@ -119,7 +119,7 @@
     </Setter>
   </Style>
 
-  <Style Selector="DatePicker:focus /template/ TextBox#PART_TextBox">
+  <Style Selector="CalendarDatePicker:focus /template/ TextBox#PART_TextBox">
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderHighBrush}"/>
   </Style>
   

src/Avalonia.Themes.Default/DefaultTheme.xaml

@@ -45,7 +45,7 @@
   <StyleInclude Source="resm:Avalonia.Themes.Default.CalendarDayButton.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.CalendarItem.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.Calendar.xaml?assembly=Avalonia.Themes.Default"/>
-  <StyleInclude Source="resm:Avalonia.Themes.Default.DatePicker.xaml?assembly=Avalonia.Themes.Default"/>
+  <StyleInclude Source="resm:Avalonia.Themes.Default.CalendarDatePicker.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.ButtonSpinner.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.NumericUpDown.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.AutoCompleteBox.xaml?assembly=Avalonia.Themes.Default"/>

src/Avalonia.Themes.Fluent/Accents/FluentBaseDark.xaml

@@ -92,6 +92,57 @@
     <StaticResource x:Key="ButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
     <StaticResource x:Key="ButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
 
+    <!-- Resources for RepeatButton.xaml -->
+    <StaticResource x:Key="RepeatButtonBackground" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="RepeatButtonBackgroundPointerOver" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="RepeatButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="RepeatButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="RepeatButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundPressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrush" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushPointerOver" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <!-- Resources for Windows.UI.Xaml.Controls.Primitives.ToggleButton -->
+    <StaticResource x:Key="ToggleButtonBackground" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundPointerOver" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundChecked" ResourceKey="SystemControlHighlightAccentBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedPointerOver" ResourceKey="SystemControlHighlightAccentBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedPressed" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminate" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminatePointerOver" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminatePressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminateDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundPressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundChecked" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedPointerOver" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedPressed" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminate" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminatePointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminatePressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminateDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrush" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushPointerOver" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushChecked" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedPointerOver" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedPressed" ResourceKey="SystemControlTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminate" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminatePointerOver" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminatePressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminateDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+
     <!-- BaseResources for ComboBox.xaml -->
     <StaticResource x:Key="ComboBoxItemForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
     <StaticResource x:Key="ComboBoxItemForegroundPressed" ResourceKey="SystemControlHighlightAltBaseHighBrush" />

src/Avalonia.Themes.Fluent/Accents/FluentBaseLight.xaml

@@ -93,6 +93,58 @@
     <StaticResource x:Key="ButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
     <StaticResource x:Key="ButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
 
+    <!-- Resources for RepeatButton.xaml -->
+    <StaticResource x:Key="RepeatButtonBackground" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="RepeatButtonBackgroundPointerOver" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="RepeatButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="RepeatButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="RepeatButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundPressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrush" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushPointerOver" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+
+    <!-- Resources for ToggleButton.xaml -->
+    <StaticResource x:Key="ToggleButtonBackground" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundPointerOver" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundChecked" ResourceKey="SystemControlHighlightAccentBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedPointerOver" ResourceKey="SystemControlHighlightAccentBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedPressed" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminate" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminatePointerOver" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminatePressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminateDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundPressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundChecked" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedPointerOver" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedPressed" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminate" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminatePointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminatePressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminateDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrush" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushPointerOver" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushChecked" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedPointerOver" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedPressed" ResourceKey="SystemControlTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminate" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminatePointerOver" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminatePressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminateDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    
     <!-- BaseResources for ComboBox.xaml -->
     <StaticResource x:Key="ComboBoxItemForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
     <StaticResource x:Key="ComboBoxItemForegroundPressed" ResourceKey="SystemControlHighlightAltBaseHighBrush" />

src/Avalonia.Themes.Fluent/Accents/FluentControlResourcesDark.xaml

@@ -39,6 +39,87 @@
     <SolidColorBrush x:Key="ButtonPressedBackgroundThemeBrush" Color="#FFFFFFFF" />
     <SolidColorBrush x:Key="ButtonPressedForegroundThemeBrush" Color="#FF000000" />
 
+    <!-- Resources for RepeatButton.xaml -->
+    <Thickness x:Key="RepeatButtonBorderThemeThickness">1</Thickness>
+    <StaticResource x:Key="RepeatButtonBackground" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <SolidColorBrush x:Key="RepeatButtonBackgroundPointerOver" Color="{StaticResource SystemBaseHighColor}" Opacity="0.1" />
+    <StaticResource x:Key="RepeatButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="RepeatButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="RepeatButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundPressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrush" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushPointerOver" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <SolidColorBrush x:Key="RepeatButtonBorderThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="RepeatButtonDisabledBackgroundThemeBrush" Color="Transparent" />
+    <SolidColorBrush x:Key="RepeatButtonDisabledBorderThemeBrush" Color="#66FFFFFF" />
+    <SolidColorBrush x:Key="RepeatButtonDisabledForegroundThemeBrush" Color="#66FFFFFF" />
+    <SolidColorBrush x:Key="RepeatButtonForegroundThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="RepeatButtonPointerOverBackgroundThemeBrush" Color="#21FFFFFF" />
+    <SolidColorBrush x:Key="RepeatButtonPointerOverForegroundThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="RepeatButtonPressedBackgroundThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="RepeatButtonPressedForegroundThemeBrush" Color="#FF000000" />
+    
+    <!-- Resources for ToggleButton.xaml -->
+    <Thickness x:Key="ToggleButtonBorderThemeThickness">1</Thickness>
+    <StaticResource x:Key="ToggleButtonBackground" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <SolidColorBrush x:Key="ToggleButtonBackgroundPointerOver" Color="{StaticResource SystemBaseHighColor}" Opacity="0.1" />
+    <StaticResource x:Key="ToggleButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundChecked" ResourceKey="SystemControlHighlightAccentBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedPointerOver" ResourceKey="SystemAccentColorDark1" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedPressed" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminate" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminatePointerOver" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminatePressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminateDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundPressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundChecked" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedPointerOver" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedPressed" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminate" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminatePointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminatePressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminateDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrush" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushPointerOver" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushChecked" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedPointerOver" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedPressed" ResourceKey="SystemControlTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminate" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminatePointerOver" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminatePressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminateDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <SolidColorBrush x:Key="ToggleButtonBackgroundThemeBrush" Color="Transparent" />
+    <SolidColorBrush x:Key="ToggleButtonBorderThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedBackgroundThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedBorderThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedDisabledBackgroundThemeBrush" Color="#66FFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedDisabledForegroundThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedForegroundThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedPointerOverBackgroundThemeBrush" Color="#99FFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedPointerOverBorderThemeBrush" Color="#99FFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedPressedBackgroundThemeBrush" Color="Transparent" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedPressedBorderThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedPressedForegroundThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonDisabledBorderThemeBrush" Color="#66FFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonDisabledForegroundThemeBrush" Color="#66FFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonForegroundThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonPointerOverBackgroundThemeBrush" Color="#21FFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonPressedBackgroundThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonPressedForegroundThemeBrush" Color="#FF000000" />
+
     <!-- Resources for ComboBox.xaml -->
     <x:Double x:Key="ComboBoxArrowThemeFontSize">21</x:Double>
     <x:Double x:Key="ComboBoxThemeMinWidth">64</x:Double>

src/Avalonia.Themes.Fluent/Accents/FluentControlResourcesLight.xaml

@@ -39,6 +39,86 @@
     <SolidColorBrush x:Key="ButtonPressedBackgroundThemeBrush" Color="#FF000000" />
     <SolidColorBrush x:Key="ButtonPressedForegroundThemeBrush" Color="#FFFFFFFF" />
 
+    <!-- Resources for RepeatButton.xaml -->
+    <Thickness x:Key="RepeatButtonBorderThemeThickness">1</Thickness>
+    <StaticResource x:Key="RepeatButtonBackground" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <SolidColorBrush x:Key="RepeatButtonBackgroundPointerOver" Color="{StaticResource SystemBaseHighColor}" Opacity="0.1" />
+    <StaticResource x:Key="RepeatButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="RepeatButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="RepeatButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundPressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="RepeatButtonForegroundDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrush" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushPointerOver" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="RepeatButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <SolidColorBrush x:Key="RepeatButtonBorderThemeBrush" Color="#33000000" />
+    <SolidColorBrush x:Key="RepeatButtonDisabledBackgroundThemeBrush" Color="#66CACACA" />
+    <SolidColorBrush x:Key="RepeatButtonDisabledBorderThemeBrush" Color="#1A000000" />
+    <SolidColorBrush x:Key="RepeatButtonDisabledForegroundThemeBrush" Color="#66000000" />
+    <SolidColorBrush x:Key="RepeatButtonForegroundThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="RepeatButtonPointerOverBackgroundThemeBrush" Color="#D1CDCDCD" />
+    <SolidColorBrush x:Key="RepeatButtonPointerOverForegroundThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="RepeatButtonPressedBackgroundThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="RepeatButtonPressedForegroundThemeBrush" Color="#FFFFFFFF" />
+    <!-- Resources for ToggleButton.xaml -->
+    <Thickness x:Key="ToggleButtonBorderThemeThickness">1</Thickness>
+    <StaticResource x:Key="ToggleButtonBackground" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <SolidColorBrush x:Key="ToggleButtonBackgroundPointerOver" Color="{StaticResource SystemBaseHighColor}" Opacity="0.1" />
+    <StaticResource x:Key="ToggleButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundChecked" ResourceKey="SystemControlHighlightAccentBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedPointerOver" ResourceKey="SystemAccentColorLight1" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedPressed" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundCheckedDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminate" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminatePointerOver" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminatePressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBackgroundIndeterminateDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="ToggleButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundPressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundChecked" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedPointerOver" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedPressed" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundCheckedDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminate" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminatePointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminatePressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="ToggleButtonForegroundIndeterminateDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrush" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushPointerOver" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushChecked" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedPointerOver" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedPressed" ResourceKey="SystemControlTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushCheckedDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminate" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminatePointerOver" ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminatePressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="ToggleButtonBorderBrushIndeterminateDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <SolidColorBrush x:Key="ToggleButtonBackgroundThemeBrush" Color="Transparent" />
+    <SolidColorBrush x:Key="ToggleButtonBorderThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedBackgroundThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedBorderThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedDisabledBackgroundThemeBrush" Color="#66000000" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedDisabledForegroundThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedForegroundThemeBrush" Color="#FFFFFFFF" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedPointerOverBackgroundThemeBrush" Color="#99000000" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedPointerOverBorderThemeBrush" Color="#99000000" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedPressedBackgroundThemeBrush" Color="Transparent" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedPressedBorderThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="ToggleButtonCheckedPressedForegroundThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="ToggleButtonDisabledBorderThemeBrush" Color="#66000000" />
+    <SolidColorBrush x:Key="ToggleButtonDisabledForegroundThemeBrush" Color="#66000000" />
+    <SolidColorBrush x:Key="ToggleButtonForegroundThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="ToggleButtonPointerOverBackgroundThemeBrush" Color="#21000000" />
+    <SolidColorBrush x:Key="ToggleButtonPressedBackgroundThemeBrush" Color="#FF000000" />
+    <SolidColorBrush x:Key="ToggleButtonPressedForegroundThemeBrush" Color="#FFFFFFFF" />
+
     <!-- Resources for ComboBox.xaml -->
     <x:Double x:Key="ComboBoxArrowThemeFontSize">21</x:Double>
     <x:Double x:Key="ComboBoxThemeMinWidth">64</x:Double>

src/Avalonia.Themes.Fluent/Accents/FluentDark.xaml

@@ -5,4 +5,5 @@
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.Accents.Base.xaml?assembly=Avalonia.Themes.Fluent" />
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.Accents.FluentBaseDark.xaml?assembly=Avalonia.Themes.Fluent" />
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.Accents.FluentControlResourcesDark.xaml?assembly=Avalonia.Themes.Fluent" />
+  <StyleInclude Source="resm:Avalonia.Themes.Fluent.FluentTheme.xaml?assembly=Avalonia.Themes.Fluent" />
 </Styles>

src/Avalonia.Themes.Fluent/Accents/FluentLight.xaml

@@ -5,4 +5,5 @@
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.Accents.Base.xaml?assembly=Avalonia.Themes.Fluent" />  
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.Accents.FluentBaseLight.xaml?assembly=Avalonia.Themes.Fluent" />
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.Accents.FluentControlResourcesLight.xaml?assembly=Avalonia.Themes.Fluent" />
+  <StyleInclude Source="resm:Avalonia.Themes.Fluent.FluentTheme.xaml?assembly=Avalonia.Themes.Fluent" />
 </Styles>

src/Avalonia.Themes.Fluent/Button.xaml

@@ -24,21 +24,19 @@
     <Setter Property="FontWeight" Value="Normal" />
     <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
     <!--<Setter Property="UseSystemFocusVisuals" Value="{StaticResource UseSystemFocusVisuals}" />
-    <Setter Property="FocusVisualMargin" Value="-3" />-->    
+    <Setter Property="FocusVisualMargin" Value="-3" />-->
     <Setter Property="Template">
       <ControlTemplate>
-        <ContentPresenter
-                        x:Name="PART_ContentPresenter"
-                        Background="{TemplateBinding Background}"
-                        BorderBrush="{TemplateBinding BorderBrush}"
-                        BorderThickness="{TemplateBinding BorderThickness}"
-                        Content="{TemplateBinding Content}"
-                        ContentTemplate="{TemplateBinding ContentTemplate}"                        
-                        CornerRadius="{DynamicResource ControlCornerRadius}"
-                        Padding="{TemplateBinding Padding}"
-                        HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
-                        VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}">
-          </ContentPresenter>        
+        <ContentPresenter x:Name="PART_ContentPresenter"
+                          Background="{TemplateBinding Background}"
+                          BorderBrush="{TemplateBinding BorderBrush}"
+                          BorderThickness="{TemplateBinding BorderThickness}"
+                          Content="{TemplateBinding Content}"
+                          ContentTemplate="{TemplateBinding ContentTemplate}"
+                          CornerRadius="{DynamicResource ControlCornerRadius}"
+                          Padding="{TemplateBinding Padding}"
+                          HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
+                          VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" />
       </ControlTemplate>
     </Setter>
   </Style>
@@ -46,19 +44,19 @@
   <!-- PointerOverState -->  
   <Style Selector="Button:pointerover /template/ ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ButtonBackgroundPointerOver}" />
-    <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrushPointerOver}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrushPointerOver}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ButtonForegroundPointerOver}" />
   </Style>
   
   <Style Selector="Button:pressed  /template/ ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ButtonBackgroundPressed}" />
-    <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrushPressed}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrushPressed}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ButtonForegroundPressed}" />
   </Style>
   
   <Style Selector="Button:disabled">
     <Setter Property="Background" Value="{DynamicResource ButtonBackgroundDisabled}" />
-    <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrushDisabled}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrushDisabled}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ButtonForegroundDisabled}" />
   </Style>
 
@@ -70,19 +68,19 @@
 
   <Style Selector="Button.accent:pointerover /template/ ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource AccentButtonBackgroundPointerOver}" />
-    <Setter Property="BorderBrush" Value="{DynamicResource AccentButtonBorderBrushPointerOver}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource AccentButtonBorderBrushPointerOver}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource AccentButtonForegroundPointerOver}" />
   </Style>
 
   <Style Selector="Button.accent:pressed  /template/ ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource AccentButtonBackgroundPressed}" />
-    <Setter Property="BorderBrush" Value="{DynamicResource AccentButtonBorderBrushPressed}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource AccentButtonBorderBrushPressed}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource AccentButtonForegroundPressed}" />
   </Style>
 
   <Style Selector="Button.accent:disabled">
     <Setter Property="Background" Value="{DynamicResource AccentButtonBackgroundDisabled}" />
-    <Setter Property="BorderBrush" Value="{DynamicResource AccentButtonBorderBrushDisabled}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource AccentButtonBorderBrushDisabled}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource AccentButtonForegroundDisabled}" />
   </Style>
 </Styles>

src/Avalonia.Themes.Default/DatePicker.xaml → src/Avalonia.Themes.Fluent/CalendarDatePicker.xaml

@@ -8,7 +8,7 @@
 <Styles xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:sys="clr-namespace:System;assembly=netstandard">
-  <Style Selector="DatePicker">
+  <Style Selector="CalendarDatePicker">
 
     <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}"/>
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}"/>
@@ -119,7 +119,7 @@
     </Setter>
   </Style>
 
-  <Style Selector="DatePicker:focus /template/ TextBox#PART_TextBox">
+  <Style Selector="CalendarDatePicker:focus /template/ TextBox#PART_TextBox">
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderHighBrush}"/>
   </Style>
   

src/Avalonia.Themes.Fluent/FluentTheme.xaml

@@ -45,7 +45,7 @@
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.CalendarDayButton.xaml?assembly=Avalonia.Themes.Fluent"/>
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.CalendarItem.xaml?assembly=Avalonia.Themes.Fluent"/>
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.Calendar.xaml?assembly=Avalonia.Themes.Fluent"/>
-  <StyleInclude Source="resm:Avalonia.Themes.Fluent.DatePicker.xaml?assembly=Avalonia.Themes.Fluent"/>
+  <StyleInclude Source="resm:Avalonia.Themes.Fluent.CalendarDatePicker.xaml?assembly=Avalonia.Themes.Fluent"/>
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.ButtonSpinner.xaml?assembly=Avalonia.Themes.Fluent"/>
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.NumericUpDown.xaml?assembly=Avalonia.Themes.Fluent"/>
   <StyleInclude Source="resm:Avalonia.Themes.Fluent.AutoCompleteBox.xaml?assembly=Avalonia.Themes.Fluent"/>

src/Avalonia.Themes.Fluent/RepeatButton.xaml

@@ -1,40 +1,62 @@
-<Styles xmlns="https://github.com/avaloniaui">
-    <Style Selector="RepeatButton">
-        <Setter Property="Background"
-                Value="{DynamicResource ThemeControlMidBrush}" />
-        <Setter Property="BorderBrush"
-                Value="{DynamicResource ThemeBorderLowBrush}" />
-        <Setter Property="BorderThickness"
-                Value="{DynamicResource ThemeBorderThickness}" />
-        <Setter Property="Foreground"
-                Value="{DynamicResource ThemeForegroundBrush}" />
-        <Setter Property="HorizontalContentAlignment"
-                Value="Center" />
-        <Setter Property="VerticalContentAlignment"
-                Value="Center" />
-        <Setter Property="Padding"
-                Value="4" />
-        <Setter Property="Template">
-            <ControlTemplate>
-                <ContentPresenter Name="PART_ContentPresenter"
-                                  Background="{TemplateBinding Background}"
-                                  BorderBrush="{TemplateBinding BorderBrush}"
-                                  BorderThickness="{TemplateBinding BorderThickness}"
-                                  ContentTemplate="{TemplateBinding ContentTemplate}"
-                                  Content="{TemplateBinding Content}"
-                                  Padding="{TemplateBinding Padding}"
-                                  TextBlock.Foreground="{TemplateBinding Foreground}"
-                                  HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
-                                  VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
-            </ControlTemplate>
-        </Setter>
-    </Style>
-    <Style Selector="RepeatButton:pointerover /template/ ContentPresenter">
-        <Setter Property="BorderBrush"
-                Value="{DynamicResource ThemeBorderMidBrush}" />
-    </Style>
-    <Style Selector="RepeatButton:disabled">
-        <Setter Property="Opacity"
-                Value="{DynamicResource ThemeDisabledOpacity}" />
-    </Style>
+<Styles xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+  <Design.PreviewWith>
+    <Border Padding="20">
+      <StackPanel Spacing="20">
+        <RepeatButton Content="Click Me!" />
+      </StackPanel>
+    </Border>
+  </Design.PreviewWith>
+  <Styles.Resources>
+    <Thickness x:Key="ButtonPadding">8,5,8,6</Thickness>
+  </Styles.Resources>
+  <Style Selector="RepeatButton">
+    <Setter Property="Background" Value="{DynamicResource RepeatButtonBackground}" />
+    <!--<Setter Property="BackgroundSizing" Value="OuterBorderEdge" />-->
+    <Setter Property="Foreground" Value="{DynamicResource RepeatButtonForeground}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource RepeatButtonBorderBrush}" />
+    <Setter Property="BorderThickness" Value="{DynamicResource ButtonBorderThemeThickness}" />
+    <Setter Property="Padding" Value="{StaticResource ButtonPadding}" />
+    <Setter Property="HorizontalAlignment" Value="Left" />
+    <Setter Property="VerticalAlignment" Value="Center" />
+    <Setter Property="FontFamily" Value="{DynamicResource ContentControlThemeFontFamily}" />
+    <Setter Property="FontWeight" Value="Normal" />
+    <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
+    <!--<Setter Property="UseSystemFocusVisuals" Value="{StaticResource UseSystemFocusVisuals}" />
+    <Setter Property="FocusVisualMargin" Value="-3" />-->
+    <Setter Property="Template">
+      <ControlTemplate>
+        <ContentPresenter x:Name="PART_ContentPresenter"
+                          Background="{TemplateBinding Background}"
+                          BorderBrush="{TemplateBinding BorderBrush}"
+                          BorderThickness="{TemplateBinding BorderThickness}"
+                          Content="{TemplateBinding Content}"
+                          ContentTemplate="{TemplateBinding ContentTemplate}"
+                          Padding="{TemplateBinding Padding}"
+                          HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
+                          VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" />
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="RepeatButton /template/ ContentPresenter">
+    <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
+  </Style>
+
+  <Style Selector="RepeatButton:pointerover /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource RepeatButtonBackgroundPointerOver}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource RepeatButtonBorderBrushPointerOver}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource RepeatButtonForegroundPointerOver}" />
+  </Style>
+
+  <Style Selector="RepeatButton:pressed  /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource RepeatButtonBackgroundPressed}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource RepeatButtonBorderBrushPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource RepeatButtonForegroundPressed}" />
+  </Style>
+
+  <Style Selector="RepeatButton:disabled">
+    <Setter Property="Background" Value="{DynamicResource RepeatButtonBackgroundDisabled}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource RepeatButtonBorderBrushDisabled}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource RepeatButtonForegroundDisabled}" />
+  </Style>
 </Styles>

src/Avalonia.Themes.Fluent/Slider.xaml

@@ -64,7 +64,7 @@
                 <TickBar Name="BottomTickBar" Placement="Bottom" Height="{DynamicResource SliderOutsideTickBarThemeHeight}" VerticalAlignment="Top" Margin="0,4,0,0" Grid.Row="2" Grid.ColumnSpan="3" />
                 <Track Name="PART_Track" Grid.Row="1" Grid.ColumnSpan="3" Orientation="Horizontal">
                   <Track.DecreaseButton>
-                    <RepeatButton Name="PART_DecreaseButton" Background="{TemplateBinding Foreground}">
+                    <RepeatButton Name="PART_DecreaseButton" Background="{TemplateBinding Foreground}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
                       <RepeatButton.Template>
                         <ControlTemplate>
                           <Grid>
@@ -76,7 +76,7 @@
                     </RepeatButton>
                   </Track.DecreaseButton>
                   <Track.IncreaseButton>
-                    <RepeatButton Name="PART_IncreaseButton" Background="{TemplateBinding Background}">
+                    <RepeatButton Name="PART_IncreaseButton" Background="{TemplateBinding Background}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
                       <RepeatButton.Template>
                         <ControlTemplate>
                           <Grid>
@@ -125,7 +125,7 @@
                 <TickBar Name="RightTickBar" Placement="Right" Width="{DynamicResource SliderOutsideTickBarThemeHeight}" HorizontalAlignment="Left" Margin="4,0,0,0" Grid.Column="2" Grid.RowSpan="3" />
                 <Track Name="PART_Track" Grid.Column="1" Grid.ColumnSpan="1" Grid.RowSpan="3" Orientation="Vertical">
                   <Track.DecreaseButton>
-                    <RepeatButton Name="PART_DecreaseButton" Background="{TemplateBinding Foreground}">
+                    <RepeatButton Name="PART_DecreaseButton" Background="{TemplateBinding Foreground}" VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
                       <RepeatButton.Template>
                         <ControlTemplate>
                           <Grid>
@@ -137,7 +137,7 @@
                     </RepeatButton>
                   </Track.DecreaseButton>
                   <Track.IncreaseButton>
-                    <RepeatButton Name="PART_IncreaseButton" Background="{TemplateBinding Background}">
+                    <RepeatButton Name="PART_IncreaseButton" Background="{TemplateBinding Background}" VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
                       <RepeatButton.Template>
                         <ControlTemplate>
                           <Grid>

src/Avalonia.Themes.Fluent/ToggleButton.xaml

@@ -1,38 +1,109 @@
-<Styles xmlns="https://github.com/avaloniaui">
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+  <Design.PreviewWith>
+    <Border Padding="20">
+      <StackPanel Spacing="20">
+        <ToggleButton Content="Click Me!" />
+        <ToggleButton Content="Disabled" IsEnabled="False" />
+        <ToggleButton Content="Three state" IsThreeState="True" />
+      </StackPanel>
+    </Border>
+  </Design.PreviewWith>
+
+  <Styles.Resources>
+    <Thickness x:Key="ButtonPadding">8,5,8,6</Thickness>
+  </Styles.Resources>
   <Style Selector="ToggleButton">
-    <Setter Property="Background" Value="{DynamicResource ThemeControlMidBrush}"/>
-    <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderLowBrush}"/>
-    <Setter Property="BorderThickness" Value="{DynamicResource ThemeBorderThickness}"/>
-    <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
-    <Setter Property="Padding" Value="4"/>
-    <Setter Property="HorizontalContentAlignment" Value="Center"/>
-    <Setter Property="VerticalContentAlignment" Value="Center"/>
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackground}" />
+    <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForeground}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrush}" />
+    <Setter Property="BorderThickness" Value="{DynamicResource ToggleButtonBorderThemeThickness}" />
+    <Setter Property="Padding" Value="{DynamicResource ButtonPadding}" />
+    <Setter Property="HorizontalAlignment" Value="Left" />
+    <Setter Property="VerticalAlignment" Value="Center" />
+    <Setter Property="FontFamily" Value="{DynamicResource ContentControlThemeFontFamily}" />
+    <Setter Property="FontWeight" Value="Normal" />
+    <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
     <Setter Property="Template">
       <ControlTemplate>
-        <ContentPresenter Name="PART_ContentPresenter"
+        <ContentPresenter x:Name="PART_ContentPresenter"
                           Background="{TemplateBinding Background}"
                           BorderBrush="{TemplateBinding BorderBrush}"
                           BorderThickness="{TemplateBinding BorderThickness}"
-                          ContentTemplate="{TemplateBinding ContentTemplate}"
+                          CornerRadius="{DynamicResource ControlCornerRadius}"
                           Content="{TemplateBinding Content}"
+                          ContentTemplate="{TemplateBinding ContentTemplate}"
                           Padding="{TemplateBinding Padding}"
-                          TextBlock.Foreground="{TemplateBinding Foreground}"
                           HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
-                          VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
+                          VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" />
       </ControlTemplate>
     </Setter>
   </Style>
-  <Style Selector="ToggleButton:checked /template/ ContentPresenter">
-    <Setter Property="Background" Value="{DynamicResource ThemeControlHighBrush}"/>
-    <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}"/>
-  </Style>
+
+  <!--  PointerOverState  -->
   <Style Selector="ToggleButton:pointerover /template/ ContentPresenter">
-    <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}"/>
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundPointerOver}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushPointerOver}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundPointerOver}" />
   </Style>
+
   <Style Selector="ToggleButton:pressed  /template/ ContentPresenter">
-    <Setter Property="Background" Value="{DynamicResource ThemeControlHighBrush}"/>
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundPressed}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundPressed}" />
+  </Style>
+
+  <Style Selector="ToggleButton:disabled /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundDisabled}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushDisabled}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundDisabled}" />
+  </Style>
+
+  <Style Selector="ToggleButton:checked /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundChecked}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushChecked}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundChecked}" />
+  </Style>
+
+  <Style Selector="ToggleButton:checked:pointerover /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundCheckedPointerOver}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushCheckedPointerOver}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundCheckedPointerOver}" />
+  </Style>
+
+  <Style Selector="ToggleButton:checked:pressed /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundCheckedPressed}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushCheckedPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundCheckedPressed}" />
+  </Style>
+
+  <Style Selector="ToggleButton:checked:disabled /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundCheckedDisabled}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushCheckedDisabled}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundCheckedDisabled}" />
+  </Style>
+
+  <Style Selector="ToggleButton:indeterminate /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminate}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminate}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminate}" />
+  </Style>
+
+  <Style Selector="ToggleButton:indeterminate:pointerover /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminatePointerOver}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminatePointerOver}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminatePointerOver}" />
+  </Style>
+
+  <Style Selector="ToggleButton:indeterminate:pressed /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminatePressed}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminatePressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminatePressed}" />
   </Style>
-  <Style Selector="ToggleButton:disabled">
-    <Setter Property="Opacity" Value="{DynamicResource ThemeDisabledOpacity}"/>
+
+  <Style Selector="ToggleButton:indeterminate:disabled /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminateDisabled}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminateDisabled}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminateDisabled}" />
   </Style>
-</Styles>
+</Styles>

src/Avalonia.Visuals/Media/DrawingContext.cs

@@ -4,6 +4,7 @@ using Avalonia.Media.Imaging;
 using Avalonia.Platform;
 using Avalonia.Rendering.SceneGraph;
 using Avalonia.Threading;
+using Avalonia.Utilities;
 using Avalonia.Visuals.Media.Imaging;
 
 namespace Avalonia.Media
@@ -154,12 +155,12 @@ namespace Avalonia.Media
                 return;
             }
 
-            if (Math.Abs(radiusX) > double.Epsilon)
+            if (!MathUtilities.IsZero(radiusX))
             {
                 radiusX = Math.Min(radiusX, rect.Width / 2);
             }
 
-            if (Math.Abs(radiusY) > double.Epsilon)
+            if (!MathUtilities.IsZero(radiusY))
             {
                 radiusY = Math.Min(radiusY, rect.Height / 2);
             }

src/Avalonia.Visuals/Media/TextFormatting/TextLayout.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using Avalonia.Media.Immutable;
 using Avalonia.Media.TextFormatting.Unicode;
 using Avalonia.Platform;
+using Avalonia.Utilities;
 using Avalonia.Utility;
 
 namespace Avalonia.Media.TextFormatting
@@ -184,7 +185,7 @@ namespace Avalonia.Media.TextFormatting
         /// </summary>
         private void UpdateLayout()
         {
-            if (_text.IsEmpty || Math.Abs(MaxWidth) < double.Epsilon || Math.Abs(MaxHeight) < double.Epsilon)
+            if (_text.IsEmpty || MathUtilities.IsZero(MaxWidth) || MathUtilities.IsZero(MaxHeight))
             {
                 var textLine = CreateEmptyTextLine(0);
 

src/Markup/Avalonia.Markup/Data/MultiBinding.cs

@@ -107,6 +107,14 @@ namespace Avalonia.Data
 
         private object ConvertValue(IList<object> values, Type targetType, IMultiValueConverter converter)
         {
+            for (var i = 0; i < values.Count; ++i)
+            {
+                if (values[i] is BindingNotification notification)
+                {
+                    values[i] = notification.Value;
+                }
+            }
+
             var culture = CultureInfo.CurrentCulture;
             var converted = converter.Convert(values, targetType, ConverterParameter, culture);
 

src/Windows/Avalonia.Direct2D1/Media/DrawingContextImpl.cs

@@ -236,7 +236,7 @@ namespace Avalonia.Direct2D1.Media
                 Math.Max(rrect.RadiiTopRight.X, Math.Max(rrect.RadiiBottomRight.X, rrect.RadiiBottomLeft.X)));
             var radiusY = Math.Max(rrect.RadiiTopLeft.Y,
                 Math.Max(rrect.RadiiTopRight.Y, Math.Max(rrect.RadiiBottomRight.Y, rrect.RadiiBottomLeft.Y)));
-            var isRounded = Math.Abs(radiusX) > double.Epsilon || Math.Abs(radiusY) > double.Epsilon;
+            var isRounded = !MathUtilities.IsZero(radiusX) || !MathUtilities.IsZero(radiusY);
 
             if (brush != null)
             {

tests/Avalonia.Base.UnitTests/Data/Core/ExpressionObserverTests_Property.cs

@@ -322,7 +322,7 @@ namespace Avalonia.Base.UnitTests.Data.Core
                 {
                     "bar",
                     new BindingNotification(
-                        new MissingMemberException("Could not find CLR property 'Bar' on 'Avalonia.Base.UnitTests.Data.Core.ExpressionObserverTests_Property+WithoutBar'"),
+                        new MissingMemberException("Could not find a matching property accessor for 'Bar' on 'Avalonia.Base.UnitTests.Data.Core.ExpressionObserverTests_Property+WithoutBar'"),
                         BindingErrorType.Error),
                     "baz",
                 },

tests/Avalonia.Base.UnitTests/Utilities/MathUtilitiesTests.cs

@@ -0,0 +1,119 @@
+using System;
+using Avalonia.Utilities;
+using Xunit;
+
+namespace Avalonia.Base.UnitTests.Utilities
+{
+    public class MathUtilitiesTests
+    {
+        private const double AnyValue = 42.42;
+        private readonly double _calculatedAnyValue;
+        private readonly double _one;
+        private readonly double _zero;
+
+        public MathUtilitiesTests()
+        {
+            _calculatedAnyValue = 0.0;
+            _one = 0.0;
+            _zero = 1.0;
+
+            const int N = 10;
+            var dxAny = AnyValue / N;
+            var dxOne = 1.0 / N;
+            var dxZero = _zero / N;
+
+            for (var i = 0; i < N; ++i)
+            {
+                _calculatedAnyValue += dxAny;
+                _one += dxOne;
+                _zero -= dxZero;
+            }
+        }
+
+        [Fact]
+        public void Two_Equivalent_Double_Values_Are_Close()
+        {
+            var actual = MathUtilities.AreClose(AnyValue, _calculatedAnyValue);
+
+            Assert.True(actual);
+            Assert.Equal(AnyValue, Math.Round(_calculatedAnyValue, 14));
+        }
+
+        [Fact]
+        public void Two_Equivalent_Single_Values_Are_Close()
+        {
+            var expectedValue = (float)AnyValue;
+            var actualValue = (float)_calculatedAnyValue;
+            
+            var actual = MathUtilities.AreClose(expectedValue, actualValue);
+
+            Assert.True(actual);
+            Assert.Equal((float) Math.Round(expectedValue, 5), (float) Math.Round(actualValue, 4));
+        }
+
+        [Fact]
+        public void Calculated_Double_One_Is_One()
+        {
+            var actual = MathUtilities.IsOne(_one);
+
+            Assert.True(actual);
+            Assert.Equal(1.0, Math.Round(_one, 15));
+        }
+
+        [Fact]
+        public void Calculated_Single_One_Is_One()
+        {
+            var actualValue = (float)_one;
+            
+            var actual = MathUtilities.IsOne(actualValue);
+
+            Assert.True(actual);
+            Assert.Equal(1.0f, (float) Math.Round(actualValue, 7));
+        }
+
+        [Fact]
+        public void Calculated_Double_Zero_Is_Zero()
+        {
+            var actual = MathUtilities.IsZero(_zero);
+
+            Assert.True(actual);
+            Assert.Equal(0.0, Math.Round(_zero, 15));
+        }
+
+        [Fact]
+        public void Calculated_Single_Zero_Is_Zero()
+        {
+            var actualValue = (float)_zero;
+
+            var actual = MathUtilities.IsZero(actualValue);
+
+            Assert.True(actual);
+            Assert.Equal(0.0f, (float) Math.Round(actualValue, 7));
+        }
+
+        [Fact]
+        public void Clamp_Input_NaN_Return_NaN()
+        {
+            var clamp = MathUtilities.Clamp(double.NaN, 0.0, 1.0);
+            Assert.True(double.IsNaN(clamp));
+        }
+
+        [Fact]
+        public void Clamp_Input_NegativeInfinity_Return_Min()
+        {
+            const double min = 0.0;
+            const double max = 1.0;
+            var actual = MathUtilities.Clamp(double.NegativeInfinity, min, max);
+            Assert.Equal(min, actual);
+        }
+
+        [Fact]
+        public void Clamp_Input_PositiveInfinity_Return_Max()
+        {
+            const double min = 0.0;
+            const double max = 1.0;
+            var actual = MathUtilities.Clamp(double.PositiveInfinity, min, max);
+            Assert.Equal(max, actual);
+        }
+    }
+}

tests/Avalonia.Benchmarks/Data/AccessorTestObject.cs

@@ -0,0 +1,47 @@
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
+using JetBrains.Annotations;
+
+namespace Avalonia.Benchmarks.Data
+{
+    internal class AccessorTestObject : INotifyPropertyChanged
+    {
+        private string _test;
+
+        public string Test
+        {
+            get => _test;
+            set
+            {
+                if (_test == value)
+                {
+                    return;
+                }
+
+                _test = value;
+
+                OnPropertyChanged();
+            }
+        }
+
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        public void Execute()
+        {
+        }
+
+        public void Execute(object p0)
+        {
+        }
+
+        public void Execute(object p0, object p1)
+        {
+        }
+
+        [NotifyPropertyChangedInvocator]
+        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
+    }
+}

tests/Avalonia.Benchmarks/Data/PropertyAccessorBenchmarks.cs

@@ -1,9 +1,6 @@
 using System;
-using System.ComponentModel;
-using System.Runtime.CompilerServices;
 using Avalonia.Data.Core.Plugins;
 using BenchmarkDotNet.Attributes;
-using JetBrains.Annotations;
 
 namespace Avalonia.Benchmarks.Data
 {
@@ -12,7 +9,7 @@ namespace Avalonia.Benchmarks.Data
     {
         private readonly InpcPropertyAccessorPlugin _inpcPlugin = new InpcPropertyAccessorPlugin();
         private readonly MethodAccessorPlugin _methodPlugin = new MethodAccessorPlugin();
-        private readonly TestObject _targetStrongRef = new TestObject();
+        private readonly AccessorTestObject _targetStrongRef = new AccessorTestObject();
         private readonly WeakReference<object> _targetWeakRef;
 
         public PropertyAccessorBenchmarks()
@@ -23,66 +20,25 @@ namespace Avalonia.Benchmarks.Data
         [Benchmark]
         public void InpcAccessorMatch()
         {
-            _inpcPlugin.Match(_targetWeakRef, nameof(TestObject.Test));
+            _inpcPlugin.Match(_targetWeakRef, nameof(AccessorTestObject.Test));
         }
 
         [Benchmark]
         public void InpcAccessorStart()
         {
-            _inpcPlugin.Start(_targetWeakRef, nameof(TestObject.Test));
+            _inpcPlugin.Start(_targetWeakRef, nameof(AccessorTestObject.Test));
         }
 
         [Benchmark]
         public void MethodAccessorMatch()
         {
-            _methodPlugin.Match(_targetWeakRef, nameof(TestObject.Execute));
+            _methodPlugin.Match(_targetWeakRef, nameof(AccessorTestObject.Execute));
         }
 
         [Benchmark]
         public void MethodAccessorStart()
         {
-            _methodPlugin.Start(_targetWeakRef, nameof(TestObject.Execute));
-        }
-
-        private class TestObject : INotifyPropertyChanged
-        {
-            private string _test;
-
-            public string Test
-            {
-                get => _test;
-                set
-                {
-                    if (_test == value)
-                    {
-                        return;
-                    }
-
-                    _test = value;
-
-                    OnPropertyChanged();
-                }
-            }
-
-            public void Execute()
-            {
-            }
-
-            public void Execute(object p0)
-            {
-            }
-
-            public void Execute(object p0, object p1)
-            {
-            }
-
-            public event PropertyChangedEventHandler PropertyChanged;
-
-            [NotifyPropertyChangedInvocator]
-            protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
-            {
-                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
-            }
+            _methodPlugin.Start(_targetWeakRef, nameof(AccessorTestObject.Execute));
         }
     }
 }

tests/Avalonia.Benchmarks/Data/PropertyAccessorPluginBenchmarks.cs

@@ -0,0 +1,60 @@
+using System.Collections.Generic;
+using Avalonia.Data.Core.Plugins;
+using BenchmarkDotNet.Attributes;
+
+namespace Avalonia.Benchmarks.Data
+{
+    [MemoryDiagnoser, InProcess]
+    public class PropertyAccessorPluginBenchmarks
+    {
+        private readonly AccessorTestObject _targetStrongRef = new AccessorTestObject();
+
+        private readonly List<IPropertyAccessorPlugin> _oldPlugins;
+        private readonly List<IPropertyAccessorPlugin> _newPlugins;
+
+        public PropertyAccessorPluginBenchmarks()
+        {
+            _oldPlugins = new List<IPropertyAccessorPlugin>
+            {
+                new AvaloniaPropertyAccessorPlugin(),
+                new MethodAccessorPlugin(),
+                new InpcPropertyAccessorPlugin()
+            };
+
+            _newPlugins = new List<IPropertyAccessorPlugin>
+            {
+                new AvaloniaPropertyAccessorPlugin(),
+                new InpcPropertyAccessorPlugin(),
+                new MethodAccessorPlugin()
+            };
+        }
+
+        [Benchmark]
+        public void MatchAccessorOld()
+        {
+            var propertyName = nameof(AccessorTestObject.Test);
+
+            foreach (IPropertyAccessorPlugin x in _oldPlugins)
+            {
+                if (x.Match(_targetStrongRef, propertyName))
+                {
+                    break;
+                }
+            }
+        }
+
+        [Benchmark]
+        public void MatchAccessorNew()
+        {
+            var propertyName = nameof(AccessorTestObject.Test);
+
+            foreach (IPropertyAccessorPlugin x in _newPlugins)
+            {
+                if (x.Match(_targetStrongRef, propertyName))
+                {
+                    break;
+                }
+            }
+        }
+    }
+}

tests/Avalonia.Controls.UnitTests/DatePickerTests.cs → tests/Avalonia.Controls.UnitTests/CalendarDatePickerTests.cs

@@ -15,7 +15,7 @@ using Xunit;
 
 namespace Avalonia.Controls.UnitTests
 {
-    public class DatePickerTests
+    public class CalendarDatePickerTests
     {
         private static bool CompareDates(DateTime first, DateTime second)
         {
@@ -30,7 +30,7 @@ namespace Avalonia.Controls.UnitTests
             using (UnitTestApplication.Start(Services))
             {
                 bool handled = false;
-                DatePicker datePicker = CreateControl();
+                CalendarDatePicker datePicker = CreateControl();
                 datePicker.SelectedDateChanged += (s,e) =>
                 {
                     handled = true;
@@ -47,7 +47,7 @@ namespace Avalonia.Controls.UnitTests
         {
             using (UnitTestApplication.Start(Services))
             {
-                DatePicker datePicker = CreateControl();
+                CalendarDatePicker datePicker = CreateControl();
                 datePicker.BlackoutDates.AddDatesInPast();
 
                 DateTime goodValue = DateTime.Today.AddDays(1);
@@ -65,7 +65,7 @@ namespace Avalonia.Controls.UnitTests
         {
             using (UnitTestApplication.Start(Services))
             {
-                DatePicker datePicker = CreateControl();
+                CalendarDatePicker datePicker = CreateControl();
                 datePicker.SelectedDate = DateTime.Today.AddDays(5);
 
                 Assert.ThrowsAny<ArgumentOutOfRangeException>(
@@ -76,10 +76,10 @@ namespace Avalonia.Controls.UnitTests
         private static TestServices Services => TestServices.MockThreadingInterface.With(
             standardCursorFactory: Mock.Of<IStandardCursorFactory>());
 
-        private DatePicker CreateControl()
+        private CalendarDatePicker CreateControl()
         {
             var datePicker =
-                new DatePicker
+                new CalendarDatePicker
                 {
                     Template = CreateTemplate()
                 };
@@ -90,7 +90,7 @@ namespace Avalonia.Controls.UnitTests
 
         private IControlTemplate CreateTemplate()
         {
-            return new FuncControlTemplate<DatePicker>((control, scope) =>
+            return new FuncControlTemplate<CalendarDatePicker>((control, scope) =>
             {
                 var textBox = 
                     new TextBox

tests/Avalonia.Controls.UnitTests/IndexRangeTests.cs

@@ -127,6 +127,88 @@ namespace Avalonia.Controls.UnitTests
             Assert.Empty(selected);
         }
 
+        [Fact]
+        public void Intersect_Should_Remove_Items_From_Beginning()
+        {
+            var ranges = new List<IndexRange> { new IndexRange(0, 10) };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(2, 12), removed);
+
+            Assert.Equal(2, result);
+            Assert.Equal(new[] { new IndexRange(2, 10) }, ranges);
+            Assert.Equal(new[] { new IndexRange(0, 1) }, removed);
+        }
+
+        [Fact]
+        public void Intersect_Should_Remove_Items_From_End()
+        {
+            var ranges = new List<IndexRange> { new IndexRange(0, 10) };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(0, 8), removed);
+
+            Assert.Equal(2, result);
+            Assert.Equal(new[] { new IndexRange(0, 8) }, ranges);
+            Assert.Equal(new[] { new IndexRange(9, 10) }, removed);
+        }
+
+        [Fact]
+        public void Intersect_Should_Remove_Entire_Range_Start()
+        {
+            var ranges = new List<IndexRange> { new IndexRange(0, 5), new IndexRange(6, 10) };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(6, 10), removed);
+
+            Assert.Equal(6, result);
+            Assert.Equal(new[] { new IndexRange(6, 10) }, ranges);
+            Assert.Equal(new[] { new IndexRange(0, 5) }, removed);
+        }
+
+        [Fact]
+        public void Intersect_Should_Remove_Entire_Range_End()
+        {
+            var ranges = new List<IndexRange> { new IndexRange(0, 5), new IndexRange(6, 10) };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(0, 4), removed);
+
+            Assert.Equal(6, result);
+            Assert.Equal(new[] { new IndexRange(0, 4) }, ranges);
+            Assert.Equal(new[] { new IndexRange(5, 10) }, removed);
+        }
+
+        [Fact]
+        public void Intersect_Should_Remove_Entire_Range_Start_End()
+        {
+            var ranges = new List<IndexRange> 
+            { 
+                new IndexRange(0, 2),
+                new IndexRange(3, 7), 
+                new IndexRange(8, 10) 
+            };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(3, 7), removed);
+
+            Assert.Equal(6, result);
+            Assert.Equal(new[] { new IndexRange(3, 7) }, ranges);
+            Assert.Equal(new[] { new IndexRange(0, 2), new IndexRange(8, 10) }, removed);
+        }
+
+        [Fact]
+        public void Intersect_Should_Remove_Entire_And_Partial_Range_Start_End()
+        {
+            var ranges = new List<IndexRange>
+            {
+                new IndexRange(0, 2),
+                new IndexRange(3, 7),
+                new IndexRange(8, 10)
+            };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(4, 6), removed);
+
+            Assert.Equal(8, result);
+            Assert.Equal(new[] { new IndexRange(4, 6) }, ranges);
+            Assert.Equal(new[] { new IndexRange(0, 3), new IndexRange(7, 10) }, removed);
+        }
+
         [Fact]
         public void Remove_Should_Remove_Entire_Range()
         {

tests/Avalonia.Controls.UnitTests/SelectionModelTests.cs

@@ -1512,6 +1512,47 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(0, raised);
         }
 
+        [Fact]
+        public void Batch_Update_Selection_Is_Correct_Throughout()
+        {
+            var data = new[] { "foo", "bar", "baz", "qux" };
+            var target = new SelectionModel { Source = data };
+            var raised = 0;
+
+            using (target.Update())
+            {
+                target.Select(1);
+
+                Assert.Equal(new IndexPath(1), target.SelectedIndex);
+                Assert.Equal(new[] { new IndexPath(1) }, target.SelectedIndices);
+                Assert.Equal("bar", target.SelectedItem);
+                Assert.Equal(new[] { "bar" }, target.SelectedItems);
+
+                target.Deselect(1);
+
+                Assert.Equal(new IndexPath(), target.SelectedIndex);
+                Assert.Empty(target.SelectedIndices);
+                Assert.Null(target.SelectedItem);
+                Assert.Empty(target.SelectedItems);
+
+                target.SelectRange(new IndexPath(1), new IndexPath(1));
+
+                Assert.Equal(new IndexPath(1), target.SelectedIndex);
+                Assert.Equal(new[] { new IndexPath(1) }, target.SelectedIndices);
+                Assert.Equal("bar", target.SelectedItem);
+                Assert.Equal(new[] { "bar" }, target.SelectedItems);
+
+                target.ClearSelection();
+
+                Assert.Equal(new IndexPath(), target.SelectedIndex);
+                Assert.Empty(target.SelectedIndices);
+                Assert.Null(target.SelectedItem);
+                Assert.Empty(target.SelectedItems);
+            }
+
+            Assert.Equal(0, raised);
+        }
+
         [Fact]
         public void AutoSelect_Selects_When_Enabled()
         {
@@ -1713,6 +1754,30 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(0, raised);
         }
 
+        [Fact]
+        public void AutoSelect_Is_Applied_At_End_Of_Batch_Update()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { AutoSelect = true, Source = data };
+
+            using (target.Update())
+            {
+                target.ClearSelection();
+
+                Assert.Equal(new IndexPath(), target.SelectedIndex);
+                Assert.Empty(target.SelectedIndices);
+                Assert.Null(target.SelectedItem);
+                Assert.Empty(target.SelectedItems);
+            }
+
+            Assert.Equal(new IndexPath(0), target.SelectedIndex);
+            Assert.Equal(new[] { new IndexPath(0) }, target.SelectedIndices);
+            Assert.Equal("foo", target.SelectedItem);
+            Assert.Equal(new[] { "foo" }, target.SelectedItems);
+
+            Assert.Equal(new IndexPath(0), target.SelectedIndex);
+        }
+
         [Fact]
         public void Can_Replace_Parent_Children_Collection()
         {
@@ -1806,6 +1871,87 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(0, node.PropertyChangedSubscriptions);
         }
 
+        [Fact]
+        public void Setting_SelectedIndex_To_Minus_1_Clears_Selection()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { Source = data };
+            target.SelectedIndex = new IndexPath(1);
+            target.SelectedIndex = new IndexPath(-1);
+            Assert.Empty(target.SelectedIndices);
+        }
+
+        [Fact]
+        public void Assigning_Source_With_Less_Items_Than_Previous_Clears_Selection()
+        {
+            var data = new[] { "foo", "bar", "baz", "boo", "hoo" };
+            var smallerData = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { RetainSelectionOnReset = true };
+            target.Source = data;
+            target.SelectedIndex = new IndexPath(4);
+            target.Source = smallerData;
+            Assert.Empty(target.SelectedIndices);
+        }
+
+        [Fact]
+        public void Initializing_Source_With_Less_Items_Than_Selection_Trims_Selection()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel();
+            target.SelectedIndex = new IndexPath(4);
+            target.Source = data;
+            Assert.Empty(target.SelectedIndices);
+        }
+
+        [Fact]
+        public void Initializing_Source_With_Less_Items_Than_Selection_Trims_Selection_RetainSelection()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { RetainSelectionOnReset = true };
+            target.SelectedIndex = new IndexPath(4);
+            target.Source = data;
+            Assert.Empty(target.SelectedIndices);
+        }
+
+        [Fact]
+        public void Initializing_Source_With_Less_Items_Than_Multiple_Selection_Trims_Selection()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { RetainSelectionOnReset = true };
+            target.Select(4);
+            target.Select(2);
+            target.Source = data;
+            Assert.Equal(1, target.SelectedIndices.Count);
+            Assert.Equal(new IndexPath(2), target.SelectedIndices.First());
+        }
+
+        [Fact]
+        public void Initializing_Source_With_Less_Items_Than_Selection_Raises_SelectionChanged()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel();
+            var raised = 0;
+
+            target.SelectedIndex = new IndexPath(4);
+
+            target.SelectionChanged += (s, e) =>
+            {
+                if (raised == 0)
+                {
+                    Assert.Equal(new[] { Path(4) }, e.DeselectedIndices);
+                    Assert.Equal(new object[] { null }, e.DeselectedItems);
+                    Assert.Empty(e.SelectedIndices);
+                    Assert.Empty(e.SelectedItems);
+                }
+
+                ++raised;
+            };
+
+            target.Source = data;
+            
+            Assert.Equal(2, raised);
+        }
+
         private int GetSubscriberCount(AvaloniaList<object> list)
         {
             return ((INotifyCollectionChangedDebug)list).GetCollectionChangedSubscribers()?.Length ?? 0;

tests/Avalonia.Controls.UnitTests/TabControlTests.cs

@@ -1,10 +1,12 @@
 using System;
+using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
 using Avalonia.Collections;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
+using Avalonia.Controls.Utils;
 using Avalonia.LogicalTree;
 using Avalonia.Styling;
 using Avalonia.UnitTests;
@@ -325,6 +327,28 @@ namespace Avalonia.Controls.UnitTests
             Assert.NotEqual(dataContext, tabItem.Content);
         }
 
+        [Fact]
+        public void Can_Have_Empty_Tab_Control()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <TabControl Name='tabs' Items='{Binding Tabs}'/>
+</Window>";
+                var loader = new Markup.Xaml.AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var tabControl = window.FindControl<TabControl>("tabs");
+
+                tabControl.DataContext = new { Tabs = new List<string>() };
+                window.ApplyTemplate();
+
+                Assert.Equal(0, tabControl.Items.Count());
+            }
+        }
+
         private IControlTemplate TabControlTemplate()
         {
             return new FuncControlTemplate<TabControl>((parent, scope) =>

tests/Avalonia.Controls.UnitTests/TreeViewTests.cs

@@ -118,313 +118,340 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Clicking_Item_Should_Select_It()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var item = tree[0].Children[1].Children[0];
-            var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
+                var item = tree[0].Children[1].Children[0];
+                var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
 
-            Assert.NotNull(container);
+                Assert.NotNull(container);
 
-            _mouse.Click(container);
+                _mouse.Click(container);
 
-            Assert.Equal(item, target.SelectedItem);
-            Assert.True(container.IsSelected);
+                Assert.Equal(item, target.SelectedItem);
+                Assert.True(container.IsSelected);
+            }
         }
 
         [Fact]
         public void Clicking_WithControlModifier_Selected_Item_Should_Deselect_It()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var item = tree[0].Children[1].Children[0];
-            var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
+                var item = tree[0].Children[1].Children[0];
+                var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
 
-            Assert.NotNull(container);
+                Assert.NotNull(container);
 
-            target.SelectedItem = item;
+                target.SelectedItem = item;
 
-            Assert.True(container.IsSelected);
+                Assert.True(container.IsSelected);
 
-            _mouse.Click(container, modifiers: KeyModifiers.Control);
+                _mouse.Click(container, modifiers: KeyModifiers.Control);
 
-            Assert.Null(target.SelectedItem);
-            Assert.False(container.IsSelected);
+                Assert.Null(target.SelectedItem);
+                Assert.False(container.IsSelected);
+            }
         }
 
         [Fact]
         public void Clicking_WithControlModifier_Not_Selected_Item_Should_Select_It()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var item1 = tree[0].Children[1].Children[0];
-            var container1 = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item1);
+                var item1 = tree[0].Children[1].Children[0];
+                var container1 = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item1);
 
-            var item2 = tree[0].Children[1];
-            var container2 = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item2);
+                var item2 = tree[0].Children[1];
+                var container2 = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item2);
 
-            Assert.NotNull(container1);
-            Assert.NotNull(container2);
+                Assert.NotNull(container1);
+                Assert.NotNull(container2);
 
-            target.SelectedItem = item1;
+                target.SelectedItem = item1;
 
-            Assert.True(container1.IsSelected);
+                Assert.True(container1.IsSelected);
 
-            _mouse.Click(container2, modifiers: KeyModifiers.Control);
-            
-            Assert.Equal(item2, target.SelectedItem);
-            Assert.False(container1.IsSelected);
-            Assert.True(container2.IsSelected);
+                _mouse.Click(container2, modifiers: KeyModifiers.Control);
+
+                Assert.Equal(item2, target.SelectedItem);
+                Assert.False(container1.IsSelected);
+                Assert.True(container2.IsSelected);
+            }
         }
 
         [Fact]
         public void Clicking_WithControlModifier_Selected_Item_Should_Deselect_And_Remove_From_SelectedItems()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var rootNode = tree[0];
+                var rootNode = tree[0];
 
-            var item1 = rootNode.Children[0];
-            var item2 = rootNode.Children.Last();
+                var item1 = rootNode.Children[0];
+                var item2 = rootNode.Children.Last();
 
-            var item1Container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item1);
-            var item2Container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item2);
+                var item1Container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item1);
+                var item2Container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item2);
 
-            ClickContainer(item1Container, KeyModifiers.Control);
-            Assert.True(item1Container.IsSelected);
+                ClickContainer(item1Container, KeyModifiers.Control);
+                Assert.True(item1Container.IsSelected);
 
-            ClickContainer(item2Container, KeyModifiers.Control);
-            Assert.True(item2Container.IsSelected);
+                ClickContainer(item2Container, KeyModifiers.Control);
+                Assert.True(item2Container.IsSelected);
 
-            Assert.Equal(new[] {item1, item2}, target.Selection.SelectedItems.OfType<Node>());
+                Assert.Equal(new[] { item1, item2 }, target.Selection.SelectedItems.OfType<Node>());
 
-            ClickContainer(item1Container, KeyModifiers.Control);
-            Assert.False(item1Container.IsSelected);
+                ClickContainer(item1Container, KeyModifiers.Control);
+                Assert.False(item1Container.IsSelected);
 
-            Assert.DoesNotContain(item1, target.Selection.SelectedItems.OfType<Node>());
+                Assert.DoesNotContain(item1, target.Selection.SelectedItems.OfType<Node>());
+            }
         }
 
         [Fact]
         public void Clicking_WithShiftModifier_DownDirection_Should_Select_Range_Of_Items()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var rootNode = tree[0];
+                var rootNode = tree[0];
 
-            var from = rootNode.Children[0];
-            var to = rootNode.Children.Last();
+                var from = rootNode.Children[0];
+                var to = rootNode.Children.Last();
 
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
 
-            ClickContainer(fromContainer, KeyModifiers.None);
+                ClickContainer(fromContainer, KeyModifiers.None);
 
-            Assert.True(fromContainer.IsSelected);
+                Assert.True(fromContainer.IsSelected);
 
-            ClickContainer(toContainer, KeyModifiers.Shift);
-            AssertChildrenSelected(target, rootNode);
+                ClickContainer(toContainer, KeyModifiers.Shift);
+                AssertChildrenSelected(target, rootNode);
+            }
         }
 
         [Fact]
         public void Clicking_WithShiftModifier_UpDirection_Should_Select_Range_Of_Items()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var rootNode = tree[0];
+                var rootNode = tree[0];
 
-            var from = rootNode.Children.Last();
-            var to = rootNode.Children[0];
+                var from = rootNode.Children.Last();
+                var to = rootNode.Children[0];
 
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
 
-            ClickContainer(fromContainer, KeyModifiers.None);
+                ClickContainer(fromContainer, KeyModifiers.None);
 
-            Assert.True(fromContainer.IsSelected);
+                Assert.True(fromContainer.IsSelected);
 
-            ClickContainer(toContainer, KeyModifiers.Shift);
-            AssertChildrenSelected(target, rootNode);
+                ClickContainer(toContainer, KeyModifiers.Shift);
+                AssertChildrenSelected(target, rootNode);
+            }
         }
 
         [Fact]
         public void Clicking_First_Item_Of_SelectedItems_Should_Select_Only_It()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var rootNode = tree[0];
+                var rootNode = tree[0];
 
-            var from = rootNode.Children.Last();
-            var to = rootNode.Children[0];
+                var from = rootNode.Children.Last();
+                var to = rootNode.Children[0];
 
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
 
-            ClickContainer(fromContainer, KeyModifiers.None);
+                ClickContainer(fromContainer, KeyModifiers.None);
 
-            ClickContainer(toContainer, KeyModifiers.Shift);
-            AssertChildrenSelected(target, rootNode);
+                ClickContainer(toContainer, KeyModifiers.Shift);
+                AssertChildrenSelected(target, rootNode);
 
-            ClickContainer(fromContainer, KeyModifiers.None);
+                ClickContainer(fromContainer, KeyModifiers.None);
 
-            Assert.True(fromContainer.IsSelected);
+                Assert.True(fromContainer.IsSelected);
 
-            foreach (var child in rootNode.Children)
-            {
-                if (child == from)
+                foreach (var child in rootNode.Children)
                 {
-                    continue;
-                }
+                    if (child == from)
+                    {
+                        continue;
+                    }
 
-                var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(child);
+                    var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(child);
 
-                Assert.False(container.IsSelected);
+                    Assert.False(container.IsSelected);
+                }
             }
         }
 
         [Fact]
         public void Setting_SelectedItem_Should_Set_Container_Selected()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var item = tree[0].Children[1].Children[0];
-            var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
+                var item = tree[0].Children[1].Children[0];
+                var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
 
-            Assert.NotNull(container);
+                Assert.NotNull(container);
 
-            target.SelectedItem = item;
+                target.SelectedItem = item;
 
-            Assert.True(container.IsSelected);
+                Assert.True(container.IsSelected);
+            }
         }
 
         [Fact]
         public void Setting_SelectedItem_Should_Raise_SelectedItemChanged_Event()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var item = tree[0].Children[1].Children[0];
+                var item = tree[0].Children[1].Children[0];
 
-            var called = false;
-            target.SelectionChanged += (s, e) =>
-            {
-                Assert.Empty(e.RemovedItems);
-                Assert.Equal(1, e.AddedItems.Count);
-                Assert.Same(item, e.AddedItems[0]);
-                called = true;
-            };
+                var called = false;
+                target.SelectionChanged += (s, e) =>
+                {
+                    Assert.Empty(e.RemovedItems);
+                    Assert.Equal(1, e.AddedItems.Count);
+                    Assert.Same(item, e.AddedItems[0]);
+                    called = true;
+                };
 
-            target.SelectedItem = item;
-            Assert.True(called);
+                target.SelectedItem = item;
+                Assert.True(called);
+            }
         }
 
         [Fact]
@@ -564,7 +591,7 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Keyboard_Navigation_Should_Move_To_Last_Selected_Node()
         {
-            using (UnitTestApplication.Start(TestServices.RealFocus))
+            using (Application())
             {
                 var focus = FocusManager.Instance;
                 var navigation = AvaloniaLocator.Current.GetService<IKeyboardNavigationHandler>();
@@ -647,7 +674,7 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Pressing_SelectAll_Gesture_With_Downward_Range_Selected_Should_Select_All_Nodes()
         {
-            using (UnitTestApplication.Start())
+            using (Application())
             {
                 var tree = CreateTestTreeData();
                 var target = new TreeView
@@ -694,7 +721,7 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Pressing_SelectAll_Gesture_With_Upward_Range_Selected_Should_Select_All_Nodes()
         {
-            using (UnitTestApplication.Start())
+            using (Application())
             {
                 var tree = CreateTestTreeData();
                 var target = new TreeView
@@ -768,97 +795,106 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Right_Click_On_UnselectedItem_Should_Clear_Existing_Selection()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
 
-            var rootNode = tree[0];
-            var to = rootNode.Children[0];
-            var then = rootNode.Children[1];
+                var rootNode = tree[0];
+                var to = rootNode.Children[0];
+                var then = rootNode.Children[1];
 
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(rootNode);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
-            var thenContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(then);
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(rootNode);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var thenContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(then);
 
-            ClickContainer(fromContainer, KeyModifiers.None);
-            ClickContainer(toContainer, KeyModifiers.Shift);
+                ClickContainer(fromContainer, KeyModifiers.None);
+                ClickContainer(toContainer, KeyModifiers.Shift);
 
-            Assert.Equal(2, target.Selection.SelectedItems.Count);
+                Assert.Equal(2, target.Selection.SelectedItems.Count);
 
-            _mouse.Click(thenContainer, MouseButton.Right);
+                _mouse.Click(thenContainer, MouseButton.Right);
 
-            Assert.Equal(1, target.Selection.SelectedItems.Count);
+                Assert.Equal(1, target.Selection.SelectedItems.Count);
+            }
         }
 
         [Fact]
         public void Shift_Right_Click_Should_Not_Select_Multiple()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
 
-            var rootNode = tree[0];
-            var from = rootNode.Children[0];
-            var to = rootNode.Children[1];
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var rootNode = tree[0];
+                var from = rootNode.Children[0];
+                var to = rootNode.Children[1];
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
 
-            _mouse.Click(fromContainer);
-            _mouse.Click(toContainer, MouseButton.Right, modifiers: KeyModifiers.Shift);
+                _mouse.Click(fromContainer);
+                _mouse.Click(toContainer, MouseButton.Right, modifiers: KeyModifiers.Shift);
 
-            Assert.Equal(1, target.Selection.SelectedItems.Count);
+                Assert.Equal(1, target.Selection.SelectedItems.Count);
+            }
         }
 
         [Fact]
         public void Ctrl_Right_Click_Should_Not_Select_Multiple()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
 
-            var rootNode = tree[0];
-            var from = rootNode.Children[0];
-            var to = rootNode.Children[1];
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var rootNode = tree[0];
+                var from = rootNode.Children[0];
+                var to = rootNode.Children[1];
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
 
-            _mouse.Click(fromContainer);
-            _mouse.Click(toContainer, MouseButton.Right, modifiers: KeyModifiers.Control);
+                _mouse.Click(fromContainer);
+                _mouse.Click(toContainer, MouseButton.Right, modifiers: KeyModifiers.Control);
 
-            Assert.Equal(1, target.Selection.SelectedItems.Count);
+                Assert.Equal(1, target.Selection.SelectedItems.Count);
+            }
         }
 
         [Fact]
@@ -944,7 +980,7 @@ namespace Avalonia.Controls.UnitTests
         public void Auto_Expanding_In_Style_Should_Not_Break_Range_Selection()
         {
             /// Issue #2980.
-            using (UnitTestApplication.Start(TestServices.RealStyler))
+            using (Application())
             {
                 var target = new DerivedTreeView
                 {
@@ -1183,12 +1219,12 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
-        void ClickContainer(IControl container, KeyModifiers modifiers)
+        private void ClickContainer(IControl container, KeyModifiers modifiers)
         {
             _mouse.Click(container, modifiers: modifiers);
         }
 
-        void AssertChildrenSelected(TreeView treeView, Node rootNode)
+        private void AssertChildrenSelected(TreeView treeView, Node rootNode)
         {
             foreach (var child in rootNode.Children)
             {
@@ -1198,6 +1234,16 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        private IDisposable Application()
+        {
+            return UnitTestApplication.Start(
+                TestServices.MockThreadingInterface.With(
+                    focusManager: new FocusManager(),
+                    keyboardDevice: () => new KeyboardDevice(),
+                    keyboardNavigation: new KeyboardNavigationHandler(),
+                    inputManager: new InputManager()));
+        }
+
         private class Node : NotifyingBase
         {
             private IAvaloniaList<Node> _children;

tests/Avalonia.Markup.UnitTests/Data/MultiBindingTests.cs

@@ -113,6 +113,50 @@ namespace Avalonia.Markup.UnitTests.Data
             Assert.Equal("(null)", target.Text);
         }
 
+        [Fact]
+        public void Should_Pass_UnsetValue_To_Converter_For_Broken_Binding()
+        {
+            var source = new { A = 1, B = 2, C = 3 };
+            var target = new TextBlock { DataContext = source };
+
+            var binding = new MultiBinding
+            {
+                Converter = new ConcatConverter(),
+                Bindings = new[]
+                {
+                    new Binding { Path = "A" },
+                    new Binding { Path = "B" },
+                    new Binding { Path = "Missing" },
+                },
+            };
+
+            target.Bind(TextBlock.TextProperty, binding);
+
+            Assert.Equal("1,2,(unset)", target.Text);
+        }
+
+        [Fact]
+        public void Should_Pass_FallbackValue_To_Converter_For_Broken_Binding()
+        {
+            var source = new { A = 1, B = 2, C = 3 };
+            var target = new TextBlock { DataContext = source };
+
+            var binding = new MultiBinding
+            {
+                Converter = new ConcatConverter(),
+                Bindings = new[]
+                {
+                    new Binding { Path = "A" },
+                    new Binding { Path = "B" },
+                    new Binding { Path = "Missing", FallbackValue = "Fallback" },
+                },
+            };
+
+            target.Bind(TextBlock.TextProperty, binding);
+
+            Assert.Equal("1,2,Fallback", target.Text);
+        }
+
         private class ConcatConverter : IMultiValueConverter
         {
             public object Convert(IList<object> values, Type targetType, object parameter, CultureInfo culture)

tests/Avalonia.Markup.UnitTests/Parsers/ExpressionObserverBuilderTests_Property.cs

@@ -22,7 +22,7 @@ namespace Avalonia.Markup.UnitTests.Parsers
 
             Assert.Equal(
                 new BindingNotification(
-                    new MissingMemberException("Could not find CLR property 'Baz' on '1'"), BindingErrorType.Error),
+                    new MissingMemberException("Could not find a matching property accessor for 'Baz' on '1'"), BindingErrorType.Error),
                 result);
 
             GC.KeepAlive(data);

tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests.cs

@@ -1,6 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
 using Avalonia.Controls;
+using Avalonia.Controls.Presenters;
 using Avalonia.Data;
+using Avalonia.Data.Converters;
 using Avalonia.UnitTests;
+using Avalonia.VisualTree;
 using Xunit;
 
 namespace Avalonia.Markup.Xaml.UnitTests.Data
@@ -54,5 +61,51 @@ namespace Avalonia.Markup.Xaml.UnitTests.Data
                 Assert.Equal("bar", textBlock.Text);
             }
         }
+
+        [Fact]
+        public void MultiBinding_TemplatedParent_Works()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Data;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <TextBox Name='textBox' Text='Foo' Watermark='Bar'>
+        <TextBox.Template>
+            <ControlTemplate>
+                <TextPresenter Name='PART_TextPresenter'>
+                    <TextPresenter.Text>
+                        <MultiBinding Converter='{x:Static local:ConcatConverter.Instance}'>
+                            <Binding RelativeSource='{RelativeSource TemplatedParent}' Path='Text'/>
+                            <Binding RelativeSource='{RelativeSource TemplatedParent}' Path='Watermark'/>
+                        </MultiBinding>
+                    </TextPresenter.Text>
+                </TextPresenter>
+            </ControlTemplate>
+        </TextBox.Template>
+    </TextBox>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var textBox = window.FindControl<TextBox>("textBox");
+
+                window.ApplyTemplate();
+                textBox.ApplyTemplate();
+
+                var target = (TextPresenter)textBox.GetVisualChildren().Single();
+                Assert.Equal("Foo,Bar", target.Text);
+            }
+        }
+    }
+
+    public class ConcatConverter : IMultiValueConverter
+    {
+        public static ConcatConverter Instance { get; } = new ConcatConverter();
+
+        public object Convert(IList<object> values, Type targetType, object parameter, CultureInfo culture)
+        {
+            return string.Join(",", values);
+        }
     }
 }