From de5dd5096efb3a52803d4f7cb207b9565020916b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Przemys=C5=82aw=20Onak?= <przemekonak@gmail.com>
Date: Thu, 3 Sep 2020 00:09:52 +0200
Subject: [PATCH 01/23] Schedule opening popup if cannot be opened right now

---
 src/Avalonia.Controls/Primitives/Popup.cs     | 21 ++++++++++++--
 .../Primitives/PopupTests.cs                  | 28 +++++++++++++++++++
 2 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/src/Avalonia.Controls/Primitives/Popup.cs b/src/Avalonia.Controls/Primitives/Popup.cs
index a676892384..1e5e80d144 100644
--- a/src/Avalonia.Controls/Primitives/Popup.cs
+++ b/src/Avalonia.Controls/Primitives/Popup.cs
@@ -128,6 +128,7 @@ namespace Avalonia.Controls.Primitives
         public static readonly StyledProperty<bool> TopmostProperty =
             AvaloniaProperty.Register<Popup, bool>(nameof(Topmost));
 
+        private bool _isOpenRequested = false;
         private bool _isOpen;
         private bool _ignoreIsOpenChanged;
         private PopupOpenState? _openState;
@@ -361,17 +362,19 @@ namespace Avalonia.Controls.Primitives
 
             if (placementTarget == null)
             {
-                throw new InvalidOperationException("Popup has no logical parent and PlacementTarget is null");
+                _isOpenRequested = true;
+                return;
             }
             
             var topLevel = placementTarget.VisualRoot as TopLevel;
 
             if (topLevel == null)
             {
-                throw new InvalidOperationException(
-                    "Attempted to open a popup not attached to a TopLevel");
+                _isOpenRequested = true;
+                return;
             }
 
+            _isOpenRequested = false;
             var popupHost = OverlayPopupHost.CreatePopupHost(placementTarget, DependencyResolver);
 
             var handlerCleanup = new CompositeDisposable(5);
@@ -492,6 +495,17 @@ namespace Avalonia.Controls.Primitives
             return new Size();
         }
 
+
+        /// <inheritdoc/>
+        protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
+        {
+            base.OnAttachedToVisualTree(e);
+            if (_isOpenRequested)
+            {
+                Open();
+            }
+        }
+
         /// <inheritdoc/>
         protected override void OnDetachedFromLogicalTree(LogicalTreeAttachmentEventArgs e)
         {
@@ -552,6 +566,7 @@ namespace Avalonia.Controls.Primitives
 
         private void CloseCore()
         {
+            _isOpenRequested = false;
             if (_openState is null)
             {
                 using (BeginIgnoringIsOpen())
diff --git a/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs b/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
index d9176ca55d..73871cf79f 100644
--- a/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
@@ -22,6 +22,34 @@ namespace Avalonia.Controls.UnitTests.Primitives
     {
         protected bool UsePopupHost;
         
+
+        [Fact]
+        public void Popup_Without_TopLevel_Shouldnt_Call_Open()
+        {
+            int openedEvent = 0;
+            var target = new Popup();
+            target.Opened += (s, a) => openedEvent++;
+            target.IsOpen = true;
+
+            Assert.Equal(0, openedEvent);
+        }
+
+        [Fact]
+        public void Opening_Popup_Shouldnt_Throw_When_Not_In_Visual_Tree()
+        {
+            var target = new Popup();
+            target.IsOpen = true;
+        }
+
+        [Fact]
+        public void Opening_Popup_Shouldnt_Throw_When_In_Tree_Without_TopLevel()
+        {
+            Control c = new Control();
+            var target = new Popup();
+            ((ISetLogicalParent)target).SetParent(c);
+            target.IsOpen = true;
+        }
+
         [Fact]
         public void Setting_Child_Should_Set_Child_Controls_LogicalParent()
         {

From db98c340d65532b136750cae5f5379c54b7c64a3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Przemys=C5=82aw=20Onak?= <przemekonak@gmail.com>
Date: Thu, 3 Sep 2020 20:47:52 +0200
Subject: [PATCH 02/23] Add test to check if popup is displayed correctly after
 window is shown

---
 .../Primitives/PopupTests.cs                    | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs b/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
index 73871cf79f..5bad646aa7 100644
--- a/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
@@ -21,7 +21,22 @@ namespace Avalonia.Controls.UnitTests.Primitives
     public class PopupTests
     {
         protected bool UsePopupHost;
-        
+
+        [Fact]
+        public void Popup_Open_Without_Target_Should_Attach_Itself_Later()
+        {
+            using (CreateServices())
+            {
+                int openedEvent = 0;
+                var target = new Popup();
+                target.Opened += (s, a) => openedEvent++;
+                target.IsOpen = true;
+
+                var window = PreparedWindow(target);
+                window.Show();
+                Assert.Equal(1, openedEvent);
+            }
+        }
 
         [Fact]
         public void Popup_Without_TopLevel_Shouldnt_Call_Open()

From f33e12c22996fbe3a23938462f5fe66de41df9fd Mon Sep 17 00:00:00 2001
From: Maksym Katsydan <maxkatz6@outlook.com>
Date: Fri, 11 Sep 2020 04:05:05 -0400
Subject: [PATCH 03/23] DataGridTextColumn: Make FontFamily, FontSize,
 FontStyle, FontWeight and Foreground properties bindable

---
 .../ApiCompatBaseline.txt                     |   5 +
 .../DataGridTextColumn.cs                     | 231 +++++-------------
 .../Utils/DataGridHelper.cs                   |  22 ++
 3 files changed, 92 insertions(+), 166 deletions(-)
 create mode 100644 src/Avalonia.Controls.DataGrid/ApiCompatBaseline.txt
 create mode 100644 src/Avalonia.Controls.DataGrid/Utils/DataGridHelper.cs

diff --git a/src/Avalonia.Controls.DataGrid/ApiCompatBaseline.txt b/src/Avalonia.Controls.DataGrid/ApiCompatBaseline.txt
new file mode 100644
index 0000000000..82472c505a
--- /dev/null
+++ b/src/Avalonia.Controls.DataGrid/ApiCompatBaseline.txt
@@ -0,0 +1,5 @@
+Compat issues with assembly Avalonia.Controls.DataGrid:
+MembersMustExist : Member 'public Avalonia.StyledProperty<System.String> Avalonia.StyledProperty<System.String> Avalonia.Controls.DataGridTextColumn.FontFamilyProperty' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public System.String Avalonia.Controls.DataGridTextColumn.FontFamily.get()' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public void Avalonia.Controls.DataGridTextColumn.FontFamily.set(System.String)' does not exist in the implementation but it does exist in the contract.
+Total Issues: 3
diff --git a/src/Avalonia.Controls.DataGrid/DataGridTextColumn.cs b/src/Avalonia.Controls.DataGrid/DataGridTextColumn.cs
index d31204b9e6..1cf6ab68ac 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridTextColumn.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridTextColumn.cs
@@ -20,11 +20,6 @@ namespace Avalonia.Controls
     {
         private const string DATAGRID_TextColumnCellTextBlockMarginKey = "DataGridTextColumnCellTextBlockMargin";
 
-        private double? _fontSize;
-        private FontStyle? _fontStyle;
-        private FontWeight? _fontWeight;
-        private IBrush _foreground;
-
         /// <summary>
         /// Initializes a new instance of the <see cref="T:Avalonia.Controls.DataGridTextColumn" /> class.
         /// </summary>
@@ -36,18 +31,24 @@ namespace Avalonia.Controls
         /// <summary>
         /// Identifies the FontFamily dependency property.
         /// </summary>
-        public static readonly StyledProperty<string> FontFamilyProperty =
-            AvaloniaProperty.Register<DataGridTextColumn, string>(nameof(FontFamily));
+        public static readonly AttachedProperty<FontFamily> FontFamilyProperty =
+            TextBlock.FontFamilyProperty.AddOwner<DataGridTextColumn>();
 
         /// <summary>
         /// Gets or sets the font name.
         /// </summary>
-        public string FontFamily
+        public FontFamily FontFamily
         {
-            get { return GetValue(FontFamilyProperty); }
-            set { SetValue(FontFamilyProperty, value); }
+            get => GetValue(FontFamilyProperty);
+            set => SetValue(FontFamilyProperty, value);
         }
 
+        /// <summary>
+        /// Identifies the FontSize dependency property.
+        /// </summary>
+        public static readonly AttachedProperty<double> FontSizeProperty =
+            TextBlock.FontSizeProperty.AddOwner<DataGridTextColumn>();
+
         /// <summary>
         /// Gets or sets the font size.
         /// </summary>
@@ -55,74 +56,66 @@ namespace Avalonia.Controls
         [DefaultValue(double.NaN)]
         public double FontSize
         {
-            get
-            {
-                return _fontSize ?? Double.NaN;
-            }
-            set
-            {
-                if (_fontSize != value)
-                {
-                    _fontSize = value;
-                    NotifyPropertyChanged(nameof(FontSize));
-                }
-            }
+            get => GetValue(FontSizeProperty);
+            set => SetValue(FontSizeProperty, value);
         }
 
+        /// <summary>
+        /// Identifies the FontStyle dependency property.
+        /// </summary>
+        public static readonly AttachedProperty<FontStyle> FontStyleProperty =
+            TextBlock.FontStyleProperty.AddOwner<DataGridTextColumn>();
+
         /// <summary>
         /// Gets or sets the font style.
         /// </summary>
         public FontStyle FontStyle
         {
-            get
-            {
-                return _fontStyle ?? FontStyle.Normal;
-            }
-            set
-            {
-                if (_fontStyle != value)
-                {
-                    _fontStyle = value;
-                    NotifyPropertyChanged(nameof(FontStyle));
-                }
-            }
+            get => GetValue(FontStyleProperty);
+            set => SetValue(FontStyleProperty, value);
         }
 
+        /// <summary>
+        /// Identifies the FontWeight dependency property.
+        /// </summary>
+        public static readonly AttachedProperty<FontWeight> FontWeightProperty =
+            TextBlock.FontWeightProperty.AddOwner<DataGridTextColumn>();
+
         /// <summary>
         /// Gets or sets the font weight or thickness.
         /// </summary>
         public FontWeight FontWeight
         {
-            get
-            {
-                return _fontWeight ?? FontWeight.Normal;
-            }
-            set
-            {
-                if (_fontWeight != value)
-                {
-                    _fontWeight = value;
-                    NotifyPropertyChanged(nameof(FontWeight));
-                }
-            }
+            get => GetValue(FontWeightProperty);
+            set => SetValue(FontWeightProperty, value);
         }
 
+        /// <summary>
+        /// Identifies the Foreground dependency property.
+        /// </summary>
+        public static readonly AttachedProperty<IBrush> ForegroundProperty =
+            TextBlock.ForegroundProperty.AddOwner<DataGridTextColumn>();
+
         /// <summary>
         /// Gets or sets a brush that describes the foreground of the column cells.
         /// </summary>
         public IBrush Foreground
         {
-            get
-            {
-                return _foreground;
-            }
-            set
+            get => GetValue(ForegroundProperty);
+            set => SetValue(ForegroundProperty, value);
+        }
+
+        protected override void OnPropertyChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
+        {
+            base.OnPropertyChanged(change);
+
+            if (change.Property == FontFamilyProperty
+                || change.Property == FontSizeProperty
+                || change.Property == FontStyleProperty
+                || change.Property == FontWeightProperty
+                || change.Property == ForegroundProperty)
             {
-                if (_foreground != value)
-                {
-                    _foreground = value;
-                    NotifyPropertyChanged(nameof(Foreground));
-                }
+                NotifyPropertyChanged(change.Property.Name);
             }
         }
 
@@ -154,26 +147,7 @@ namespace Avalonia.Controls
                 Background = new SolidColorBrush(Colors.Transparent)
             };
 
-            if (IsSet(FontFamilyProperty))
-            {
-                textBox.FontFamily = FontFamily;
-            }
-            if (_fontSize.HasValue)
-            {
-                textBox.FontSize = _fontSize.Value;
-            }
-            if (_fontStyle.HasValue)
-            {
-                textBox.FontStyle = _fontStyle.Value;
-            }
-            if (_fontWeight.HasValue)
-            {
-                textBox.FontWeight = _fontWeight.Value;
-            }
-            if (_foreground != null)
-            {
-                textBox.Foreground = _foreground;
-            }
+            SyncProperties(textBox);
 
             return textBox;
         }
@@ -192,26 +166,8 @@ namespace Avalonia.Controls
                 VerticalAlignment = VerticalAlignment.Center
             };
 
-            if (IsSet(FontFamilyProperty))
-            {
-                textBlockElement.FontFamily = FontFamily;
-            }
-            if (_fontSize.HasValue)
-            {
-                textBlockElement.FontSize = _fontSize.Value;
-            }
-            if (_fontStyle.HasValue)
-            {
-                textBlockElement.FontStyle = _fontStyle.Value;
-            }
-            if (_fontWeight.HasValue)
-            {
-                textBlockElement.FontWeight = _fontWeight.Value;
-            }
-            if (_foreground != null)
-            {
-                textBlockElement.Foreground = _foreground;
-            }
+            SyncProperties(textBlockElement);
+
             if (Binding != null)
             {
                 textBlockElement.Bind(TextBlock.TextProperty, Binding);
@@ -261,99 +217,42 @@ namespace Avalonia.Controls
                 throw new ArgumentNullException("element");
             }
 
-            if(element is TextBox textBox)
+            if (element is AvaloniaObject content)
             {
                 if (propertyName == nameof(FontFamily))
                 {
-                    textBox.FontFamily = FontFamily;
+                    DataGridHelper.SyncColumnProperty(this, content, FontFamilyProperty);
                 }
                 else if (propertyName == nameof(FontSize))
                 {
-                    SetTextFontSize(textBox, TextBox.FontSizeProperty);
+                    DataGridHelper.SyncColumnProperty(this, content, FontSizeProperty);
                 }
                 else if (propertyName == nameof(FontStyle))
                 {
-                    textBox.FontStyle = FontStyle;
+                    DataGridHelper.SyncColumnProperty(this, content, FontStyleProperty);
                 }
                 else if (propertyName == nameof(FontWeight))
                 {
-                    textBox.FontWeight = FontWeight;
+                    DataGridHelper.SyncColumnProperty(this, content, FontWeightProperty);
                 }
                 else if (propertyName == nameof(Foreground))
                 {
-                    textBox.Foreground = Foreground;
-                }
-                else
-                {
-                    if (FontFamily != null)
-                    {
-                        textBox.FontFamily = FontFamily;
-                    }
-                    SetTextFontSize(textBox, TextBox.FontSizeProperty);
-                    textBox.FontStyle = FontStyle;
-                    textBox.FontWeight = FontWeight;
-                    if (Foreground != null)
-                    {
-                        textBox.Foreground = Foreground;
-                    }
-                }
-
-            }
-            else if (element is TextBlock textBlock)
-            {
-                if (propertyName == nameof(FontFamily))
-                {
-                    textBlock.FontFamily = FontFamily;
-                }
-                else if (propertyName == nameof(FontSize))
-                {
-                    SetTextFontSize(textBlock, TextBlock.FontSizeProperty);
-                }
-                else if (propertyName == nameof(FontStyle))
-                {
-                    textBlock.FontStyle = FontStyle;
-                }
-                else if (propertyName == nameof(FontWeight))
-                {
-                    textBlock.FontWeight = FontWeight;
-                }
-                else if (propertyName == nameof(Foreground))
-                {
-                    textBlock.Foreground = Foreground;
-                }
-                else
-                {
-                    if (FontFamily != null)
-                    {
-                        textBlock.FontFamily = FontFamily;
-                    }
-                    SetTextFontSize(textBlock, TextBlock.FontSizeProperty);
-                    textBlock.FontStyle = FontStyle;
-                    textBlock.FontWeight = FontWeight;
-                    if (Foreground != null)
-                    {
-                        textBlock.Foreground = Foreground;
-                    }
+                    DataGridHelper.SyncColumnProperty(this, content, ForegroundProperty);
                 }
             }
             else
             {
-                throw DataGridError.DataGrid.ValueIsNotAnInstanceOfEitherOr("element", typeof(TextBox), typeof(TextBlock));
+                throw DataGridError.DataGrid.ValueIsNotAnInstanceOf("element", typeof(AvaloniaObject));
             }
         }
 
-        private void SetTextFontSize(AvaloniaObject textElement, AvaloniaProperty fontSizeProperty)
+        private void SyncProperties(AvaloniaObject content)
         {
-            double newFontSize = FontSize;
-            if (double.IsNaN(newFontSize))
-            {
-                textElement.ClearValue(fontSizeProperty);
-            }
-            else
-            {
-                textElement.SetValue(fontSizeProperty, newFontSize);
-            }
+            DataGridHelper.SyncColumnProperty(this, content, FontFamilyProperty);
+            DataGridHelper.SyncColumnProperty(this, content, FontSizeProperty);
+            DataGridHelper.SyncColumnProperty(this, content, FontStyleProperty);
+            DataGridHelper.SyncColumnProperty(this, content, FontWeightProperty);
+            DataGridHelper.SyncColumnProperty(this, content, ForegroundProperty);
         }
-
     }
 }
diff --git a/src/Avalonia.Controls.DataGrid/Utils/DataGridHelper.cs b/src/Avalonia.Controls.DataGrid/Utils/DataGridHelper.cs
new file mode 100644
index 0000000000..d553a82fa0
--- /dev/null
+++ b/src/Avalonia.Controls.DataGrid/Utils/DataGridHelper.cs
@@ -0,0 +1,22 @@
+namespace Avalonia.Controls
+{
+    public static class DataGridHelper
+    {
+        internal static void SyncColumnProperty<T>(AvaloniaObject column, AvaloniaObject content, AvaloniaProperty<T> property)
+        {
+            SyncColumnProperty(column, content, property, property);
+        }
+
+        internal static void SyncColumnProperty<T>(AvaloniaObject column, AvaloniaObject content, AvaloniaProperty<T> contentProperty, AvaloniaProperty<T> columnProperty)
+        {
+            if (!column.IsSet(columnProperty))
+            {
+                content.ClearValue(contentProperty);
+            }
+            else
+            {
+                content.SetValue(contentProperty, column.GetValue(columnProperty));
+            }
+        }
+    }
+}

From ab5c3dd190088d80464edbdd76bb366b7ae52bab Mon Sep 17 00:00:00 2001
From: Maksym Katsydan <maxkatz6@outlook.com>
Date: Fri, 11 Sep 2020 04:06:10 -0400
Subject: [PATCH 04/23] DataGridCheckBoxColumn: Make IsThreeState property
 bindable

---
 .../DataGridCheckBoxColumn.cs                 | 34 +++++++++++--------
 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/src/Avalonia.Controls.DataGrid/DataGridCheckBoxColumn.cs b/src/Avalonia.Controls.DataGrid/DataGridCheckBoxColumn.cs
index f1bbea9949..e2a067ac61 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridCheckBoxColumn.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridCheckBoxColumn.cs
@@ -17,9 +17,7 @@ namespace Avalonia.Controls
     /// </summary>
     public class DataGridCheckBoxColumn : DataGridBoundColumn
     {
-
         private bool _beganEditWithKeyboard;
-        private bool _isThreeState;
         private CheckBox _currentCheckBox;
         private DataGrid _owningGrid;
 
@@ -31,6 +29,12 @@ namespace Avalonia.Controls
             BindingTarget = CheckBox.IsCheckedProperty;
         }
 
+        /// <summary>
+        /// Defines the <see cref="IsThreeState"/> property.
+        /// </summary>
+        public static StyledProperty<bool> IsThreeStateProperty =
+            CheckBox.IsThreeStateProperty.AddOwner<DataGridCheckBoxColumn>();
+
         /// <summary>
         /// Gets or sets a value that indicates whether the hosted <see cref="T:System.Windows.Controls.CheckBox" /> controls allow three states or two. 
         /// </summary>
@@ -39,17 +43,17 @@ namespace Avalonia.Controls
         /// </returns>
         public bool IsThreeState
         {
-            get
-            {
-                return _isThreeState;
-            }
-            set
+            get => GetValue(IsThreeStateProperty);
+            set => SetValue(IsThreeStateProperty, value);
+        }
+
+        protected override void OnPropertyChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
+        {
+            base.OnPropertyChanged(change);
+
+            if (change.Property == IsThreeStateProperty)
             {
-                if (_isThreeState != value)
-                {
-                    _isThreeState = value;
-                    NotifyPropertyChanged(nameof(IsThreeState));
-                }
+                NotifyPropertyChanged(change.Property.Name);
             }
         }
 
@@ -203,9 +207,9 @@ namespace Avalonia.Controls
             {
                 throw new ArgumentNullException("element");
             }
-            if(element is CheckBox checkBox)
+            if (element is CheckBox checkBox)
             {
-                checkBox.IsThreeState = IsThreeState;
+                DataGridHelper.SyncColumnProperty(this, checkBox, IsThreeStateProperty);
             }
             else
             {
@@ -229,7 +233,7 @@ namespace Avalonia.Controls
         {
             checkBox.HorizontalAlignment = HorizontalAlignment.Center;
             checkBox.VerticalAlignment = VerticalAlignment.Center;
-            checkBox.IsThreeState = IsThreeState;
+            DataGridHelper.SyncColumnProperty(this, checkBox, IsThreeStateProperty);
         }
 
         private bool EnsureOwningGrid()

From fae969644a110f1a78b9d9307de9eeefa7cc86c7 Mon Sep 17 00:00:00 2001
From: Maksym Katsydan <maxkatz6@outlook.com>
Date: Fri, 11 Sep 2020 04:11:02 -0400
Subject: [PATCH 05/23] Update DataGrid sample page to test column bindings

---
 samples/ControlCatalog/Pages/DataGridPage.xaml | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/samples/ControlCatalog/Pages/DataGridPage.xaml b/samples/ControlCatalog/Pages/DataGridPage.xaml
index d045626c2c..cacc2204bd 100644
--- a/samples/ControlCatalog/Pages/DataGridPage.xaml
+++ b/samples/ControlCatalog/Pages/DataGridPage.xaml
@@ -11,12 +11,17 @@
       <Setter Property="Background" Value="{Binding Path=GDP, Mode=OneWay, Converter={StaticResource GDPConverter}}" />
     </Style>
   </UserControl.Styles>
-  <Grid RowDefinitions="Auto,*">
+  <Grid RowDefinitions="Auto,Auto,*">
     <StackPanel Orientation="Vertical" Spacing="4" Grid.Row="0">
       <TextBlock Classes="h1">DataGrid</TextBlock>
       <TextBlock Classes="h2">A control for displaying and interacting with a data source.</TextBlock>
     </StackPanel>
-    <TabControl Grid.Row="1">
+    <StackPanel Grid.Row="1" Spacing="4" Orientation="Horizontal" IsVisible="{Binding #EditableTab.IsSelected}">
+      <TextBlock Text="FontSize:" VerticalAlignment="Center"/>
+      <Slider x:Name="FontSizeSlider" Minimum="5" Maximum="30" Value="14" Width="100" VerticalAlignment="Center" />
+      <CheckBox x:Name="IsThreeStateCheckBox" IsChecked="False" Content="IsThreeState"/>
+    </StackPanel>
+    <TabControl Grid.Row="2">
       <TabItem Header="DataGrid">
         <DataGrid Name="dataGrid1" Margin="12" CanUserResizeColumns="True" CanUserReorderColumns="True" CanUserSortColumns="True" HeadersVisibility="All">
           <DataGrid.Columns>
@@ -39,13 +44,13 @@
           </DataGrid.Columns>
         </DataGrid>
       </TabItem>
-      <TabItem Header="Editable">
+      <TabItem x:Name="EditableTab" Header="Editable">
         <Grid RowDefinitions="*,Auto">
           <DataGrid Name="dataGridEdit" Margin="12" Grid.Row="0">
             <DataGrid.Columns>
-              <DataGridTextColumn Header="First Name" Binding="{Binding FirstName}" Width="2*" />
-              <DataGridTextColumn Header="Last" Binding="{Binding LastName}" Width="2*" />
-              <DataGridCheckBoxColumn Header="Is Banned" Binding="{Binding IsBanned}" Width="*" />
+              <DataGridTextColumn Header="First Name" Binding="{Binding FirstName}" Width="2*" FontSize="{Binding #FontSizeSlider.Value, Mode=OneWay}" />
+              <DataGridTextColumn Header="Last" Binding="{Binding LastName}" Width="2*" FontSize="{Binding #FontSizeSlider.Value, Mode=OneWay}" />
+              <DataGridCheckBoxColumn Header="Is Banned" Binding="{Binding IsBanned}" Width="*" IsThreeState="{Binding #IsThreeStateCheckBox.IsChecked, Mode=OneWay}" />
             </DataGrid.Columns>
           </DataGrid>
           <Button Grid.Row="1" Name="btnAdd" Margin="12,0,12,12" Content="Add" HorizontalAlignment="Right" />

From e058defbc11f3a4cfb9e363ce6aaec8408fb194a Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Fri, 11 Sep 2020 13:29:06 -0400
Subject: [PATCH 06/23] Make DataGridHelper internal

---
 src/Avalonia.Controls.DataGrid/Utils/DataGridHelper.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Avalonia.Controls.DataGrid/Utils/DataGridHelper.cs b/src/Avalonia.Controls.DataGrid/Utils/DataGridHelper.cs
index d553a82fa0..2cf41082ca 100644
--- a/src/Avalonia.Controls.DataGrid/Utils/DataGridHelper.cs
+++ b/src/Avalonia.Controls.DataGrid/Utils/DataGridHelper.cs
@@ -1,6 +1,6 @@
 namespace Avalonia.Controls
 {
-    public static class DataGridHelper
+    internal static class DataGridHelper
     {
         internal static void SyncColumnProperty<T>(AvaloniaObject column, AvaloniaObject content, AvaloniaProperty<T> property)
         {

From f3e0863f529e8dc6b010e6a4cc6764ad6bb151f6 Mon Sep 17 00:00:00 2001
From: Kieran Devlin <kierandevvs@gmail.com>
Date: Sat, 19 Sep 2020 17:20:18 +0100
Subject: [PATCH 07/23] Updated exception type for validation exceptions so
 that DataValidationErrors can extract the user friendly message.

---
 .../Data/Core/Plugins/DataAnnotationsValidationPlugin.cs      | 4 ++--
 .../Data/Core/Plugins/DataAnnotationsValidationPluginTests.cs | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/Avalonia.Base/Data/Core/Plugins/DataAnnotationsValidationPlugin.cs b/src/Avalonia.Base/Data/Core/Plugins/DataAnnotationsValidationPlugin.cs
index 3b61f6d898..f052283b22 100644
--- a/src/Avalonia.Base/Data/Core/Plugins/DataAnnotationsValidationPlugin.cs
+++ b/src/Avalonia.Base/Data/Core/Plugins/DataAnnotationsValidationPlugin.cs
@@ -63,12 +63,12 @@ namespace Avalonia.Data.Core.Plugins
             {
                 if (errors.Count == 1)
                 {
-                    return new ValidationException(errors[0].ErrorMessage);
+                    return new DataValidationException(errors[0].ErrorMessage);
                 }
                 else
                 {
                     return new AggregateException(
-                        errors.Select(x => new ValidationException(x.ErrorMessage)));
+                        errors.Select(x => new DataValidationException(x.ErrorMessage)));
                 }
             }
         }
diff --git a/tests/Avalonia.Base.UnitTests/Data/Core/Plugins/DataAnnotationsValidationPluginTests.cs b/tests/Avalonia.Base.UnitTests/Data/Core/Plugins/DataAnnotationsValidationPluginTests.cs
index 5c8a941294..1d9524a191 100644
--- a/tests/Avalonia.Base.UnitTests/Data/Core/Plugins/DataAnnotationsValidationPluginTests.cs
+++ b/tests/Avalonia.Base.UnitTests/Data/Core/Plugins/DataAnnotationsValidationPluginTests.cs
@@ -59,12 +59,12 @@ namespace Avalonia.Markup.UnitTests.Data.Plugins
             {
                 new BindingNotification(5),
                 new BindingNotification(
-                    new ValidationException(errmsg),
+                    new DataValidationException(errmsg),
                     BindingErrorType.DataValidationError,
                     3),
                 new BindingNotification(7),
                 new BindingNotification(
-                    new ValidationException(errmsg),
+                    new DataValidationException(errmsg),
                     BindingErrorType.DataValidationError,
                     11),
             }, result);

From e7f80f7acea318c661708dbe0c8292c7be220fd0 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Wed, 23 Sep 2020 10:50:36 +0200
Subject: [PATCH 08/23] Correctly style submenu scrollers.

---
 src/Avalonia.Themes.Default/MenuItem.xaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Avalonia.Themes.Default/MenuItem.xaml b/src/Avalonia.Themes.Default/MenuItem.xaml
index 7d7d06dd55..741cf1b79c 100644
--- a/src/Avalonia.Themes.Default/MenuItem.xaml
+++ b/src/Avalonia.Themes.Default/MenuItem.xaml
@@ -64,7 +64,7 @@
               <Border Background="{TemplateBinding Background}"
                       BorderBrush="{DynamicResource ThemeBorderMidBrush}"
                       BorderThickness="{TemplateBinding BorderThickness}">
-                <ScrollViewer>                  
+                <ScrollViewer Classes="menuscroller">                  
                     <ItemsPresenter Name="PART_ItemsPresenter"
                                     Items="{TemplateBinding Items}"
                                     ItemsPanel="{TemplateBinding ItemsPanel}"

From 4a1db02d7d75bcfb997485f33951d6093437662f Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Wed, 23 Sep 2020 11:33:39 +0200
Subject: [PATCH 09/23] Style fluent menu scrollers.

---
 src/Avalonia.Themes.Fluent/ContextMenu.xaml  |  2 +-
 src/Avalonia.Themes.Fluent/MenuItem.xaml     |  4 +-
 src/Avalonia.Themes.Fluent/ScrollViewer.xaml | 64 +++++++++++++++++++-
 3 files changed, 66 insertions(+), 4 deletions(-)

diff --git a/src/Avalonia.Themes.Fluent/ContextMenu.xaml b/src/Avalonia.Themes.Fluent/ContextMenu.xaml
index 6ad038676b..33447ffd6c 100644
--- a/src/Avalonia.Themes.Fluent/ContextMenu.xaml
+++ b/src/Avalonia.Themes.Fluent/ContextMenu.xaml
@@ -49,7 +49,7 @@
               MinHeight="{TemplateBinding MinHeight}"
               HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
               CornerRadius="{DynamicResource OverlayCornerRadius}">
-        <ScrollViewer>
+        <ScrollViewer Classes="menuscroller">
           <ItemsPresenter Name="PART_ItemsPresenter"
                           Items="{TemplateBinding Items}"
                           ItemsPanel="{TemplateBinding ItemsPanel}"
diff --git a/src/Avalonia.Themes.Fluent/MenuItem.xaml b/src/Avalonia.Themes.Fluent/MenuItem.xaml
index 3a03ec1acf..1f1dcf22e2 100644
--- a/src/Avalonia.Themes.Fluent/MenuItem.xaml
+++ b/src/Avalonia.Themes.Fluent/MenuItem.xaml
@@ -123,7 +123,7 @@
                     MinHeight="{DynamicResource MenuFlyoutThemeMinHeight}"
                     HorizontalAlignment="Stretch"
                     CornerRadius="{DynamicResource OverlayCornerRadius}">
-              <ScrollViewer>
+              <ScrollViewer Classes="menuscroller">
                 <ItemsPresenter Name="PART_ItemsPresenter"
                                 Items="{TemplateBinding Items}"
                                 ItemsPanel="{TemplateBinding ItemsPanel}"
@@ -171,7 +171,7 @@
                       MinHeight="{DynamicResource MenuFlyoutThemeMinHeight}"
                       HorizontalAlignment="Stretch"
                       CornerRadius="{DynamicResource OverlayCornerRadius}">
-                <ScrollViewer>
+                <ScrollViewer Classes="menuscroller">
                   <ItemsPresenter Name="PART_ItemsPresenter"
                                   Items="{TemplateBinding Items}"
                                   ItemsPanel="{TemplateBinding ItemsPanel}"
diff --git a/src/Avalonia.Themes.Fluent/ScrollViewer.xaml b/src/Avalonia.Themes.Fluent/ScrollViewer.xaml
index fb73f7eab1..e36eb5e77c 100644
--- a/src/Avalonia.Themes.Fluent/ScrollViewer.xaml
+++ b/src/Avalonia.Themes.Fluent/ScrollViewer.xaml
@@ -1,4 +1,6 @@
-<Styles xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:converters="clr-namespace:Avalonia.Controls.Converters;assembly=Avalonia.Controls">
 
   <Style Selector="ScrollViewer">
     <Setter Property="Background"
@@ -66,4 +68,64 @@
     <Setter Property="Opacity" Value="1" />
   </Style>
 
+  <Style Selector="ScrollViewer.menuscroller">
+    <Setter Property="Template">
+      <ControlTemplate>
+        <DockPanel>
+          <RepeatButton DockPanel.Dock="Top"
+                        BorderThickness="0"
+                        Background="Transparent"
+                        HorizontalAlignment="Stretch"
+                        HorizontalContentAlignment="Center"
+                        RenderTransform="{x:Null}"
+                        Command="{Binding LineUp, RelativeSource={RelativeSource TemplatedParent}}">
+            <RepeatButton.IsVisible>
+              <MultiBinding Converter="{x:Static converters:MenuScrollingVisibilityConverter.Instance}"
+                            ConverterParameter="0">
+                <Binding RelativeSource="{RelativeSource TemplatedParent}" Path="VerticalScrollBarVisibility"/>
+                <Binding RelativeSource="{RelativeSource TemplatedParent}" Path="Offset.Y"/>
+                <Binding RelativeSource="{RelativeSource TemplatedParent}" Path="Extent.Height"/>
+                <Binding RelativeSource="{RelativeSource TemplatedParent}" Path="Viewport.Height"/>
+              </MultiBinding>
+            </RepeatButton.IsVisible>
+            <Path Data="M 0 4 L 8 4 L 4 0 Z"/>
+          </RepeatButton>
+          <RepeatButton DockPanel.Dock="Bottom"
+                        BorderThickness="0"
+                        Background="Transparent"
+                        HorizontalAlignment="Stretch"
+                        HorizontalContentAlignment="Center"
+                        RenderTransform="{x:Null}"
+                        Command="{Binding LineDown, RelativeSource={RelativeSource TemplatedParent}}">
+            <RepeatButton.IsVisible>
+              <MultiBinding Converter="{x:Static converters:MenuScrollingVisibilityConverter.Instance}"
+                            ConverterParameter="100">
+                <Binding RelativeSource="{RelativeSource TemplatedParent}" Path="VerticalScrollBarVisibility"/>
+                <Binding RelativeSource="{RelativeSource TemplatedParent}" Path="Offset.Y"/>
+                <Binding RelativeSource="{RelativeSource TemplatedParent}" Path="Extent.Height"/>
+                <Binding RelativeSource="{RelativeSource TemplatedParent}" Path="Viewport.Height"/>
+              </MultiBinding>
+            </RepeatButton.IsVisible>
+            <Path Data="M 0 0 L 4 4 L 8 0 Z"/>
+          </RepeatButton>
+          <ScrollContentPresenter Name="PART_ContentPresenter"
+                                  CanHorizontallyScroll="{TemplateBinding CanHorizontallyScroll}"
+                                  CanVerticallyScroll="{TemplateBinding CanVerticallyScroll}"
+                                  Content="{TemplateBinding Content}"
+                                  Extent="{TemplateBinding Extent, Mode=TwoWay}"
+                                  Margin="{TemplateBinding Padding}"
+                                  Offset="{TemplateBinding Offset, Mode=TwoWay}"
+                                  Viewport="{TemplateBinding Viewport, Mode=TwoWay}"/>
+        </DockPanel>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+  <Style Selector="ScrollViewer.menuscroller /template/ RepeatButton > Path">
+    <Setter Property="Fill" Value="{DynamicResource ScrollBarButtonArrowForeground}" />
+  </Style>
+
+  <Style Selector="ScrollViewer.menuscroller /template/ RepeatButton:pointerover > Path">
+    <Setter Property="Fill" Value="{DynamicResource ScrollBarButtonArrowForegroundPointerOver}" />
+  </Style>
+
 </Styles>

From f5c310e187f82f89878710497a47967d2909d428 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sat, 26 Sep 2020 23:07:27 -0400
Subject: [PATCH 10/23] Fluent icons in ScrollViewer.menuscroller

---
 src/Avalonia.Themes.Fluent/ScrollViewer.xaml | 36 +++++++++++++++++---
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/src/Avalonia.Themes.Fluent/ScrollViewer.xaml b/src/Avalonia.Themes.Fluent/ScrollViewer.xaml
index e36eb5e77c..640b8de89f 100644
--- a/src/Avalonia.Themes.Fluent/ScrollViewer.xaml
+++ b/src/Avalonia.Themes.Fluent/ScrollViewer.xaml
@@ -2,6 +2,20 @@
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:converters="clr-namespace:Avalonia.Controls.Converters;assembly=Avalonia.Controls">
 
+  <Design.PreviewWith>
+    <Grid ColumnDefinitions="*,20,*"
+          Height="300"
+          Width="200"
+          Margin="20">
+      <ScrollViewer>
+        <Border Height="1000" Background="#ccc"/>
+      </ScrollViewer>
+      <ScrollViewer Grid.Column="2" Classes="menuscroller">
+        <Border Height="1000" Background="#ccc"/>
+      </ScrollViewer>
+    </Grid>
+  </Design.PreviewWith>
+  
   <Style Selector="ScrollViewer">
     <Setter Property="Background"
             Value="Transparent" />
@@ -88,7 +102,14 @@
                 <Binding RelativeSource="{RelativeSource TemplatedParent}" Path="Viewport.Height"/>
               </MultiBinding>
             </RepeatButton.IsVisible>
-            <Path Data="M 0 4 L 8 4 L 4 0 Z"/>
+            <Viewbox Width="{DynamicResource ScrollBarButtonArrowIconFontSize}"
+                     Height="{DynamicResource ScrollBarButtonArrowIconFontSize}">
+              <Path VerticalAlignment="Center"
+                    HorizontalAlignment="Center"
+                    Data="M 19.091797 14.970703 L 10 5.888672 L 0.908203 14.970703 L 0.029297 14.091797 L 10 4.111328 L 19.970703 14.091797 Z"
+                    Width="20"
+                    Height="20" />
+            </Viewbox>
           </RepeatButton>
           <RepeatButton DockPanel.Dock="Bottom"
                         BorderThickness="0"
@@ -106,7 +127,14 @@
                 <Binding RelativeSource="{RelativeSource TemplatedParent}" Path="Viewport.Height"/>
               </MultiBinding>
             </RepeatButton.IsVisible>
-            <Path Data="M 0 0 L 4 4 L 8 0 Z"/>
+            <Viewbox Width="{DynamicResource ScrollBarButtonArrowIconFontSize}"
+                     Height="{DynamicResource ScrollBarButtonArrowIconFontSize}">
+              <Path VerticalAlignment="Center"
+                    HorizontalAlignment="Center"
+                    Data="M 18.935547 4.560547 L 19.814453 5.439453 L 10 15.253906 L 0.185547 5.439453 L 1.064453 4.560547 L 10 13.496094 Z"
+                    Width="20"
+                    Height="20" />
+            </Viewbox>
           </RepeatButton>
           <ScrollContentPresenter Name="PART_ContentPresenter"
                                   CanHorizontallyScroll="{TemplateBinding CanHorizontallyScroll}"
@@ -120,11 +148,11 @@
       </ControlTemplate>
     </Setter>
   </Style>
-  <Style Selector="ScrollViewer.menuscroller /template/ RepeatButton > Path">
+  <Style Selector="ScrollViewer.menuscroller /template/ RepeatButton > Viewbox > Path">
     <Setter Property="Fill" Value="{DynamicResource ScrollBarButtonArrowForeground}" />
   </Style>
 
-  <Style Selector="ScrollViewer.menuscroller /template/ RepeatButton:pointerover > Path">
+  <Style Selector="ScrollViewer.menuscroller /template/ RepeatButton:pointerover > Viewbox > Path">
     <Setter Property="Fill" Value="{DynamicResource ScrollBarButtonArrowForegroundPointerOver}" />
   </Style>
 

From c8323af3b1c616f6ecd27fe1a07ea8bf5e6e43bd Mon Sep 17 00:00:00 2001
From: Giuseppe Lippolis <workgroupengineering@outlook.com>
Date: Fri, 25 Sep 2020 16:12:17 +0200
Subject: [PATCH 11/23] Fix NRE int ItemContainerGenerator when item is null

---
 .../Generators/ItemContainerGenerator`1.cs                  | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/src/Avalonia.Controls/Generators/ItemContainerGenerator`1.cs b/src/Avalonia.Controls/Generators/ItemContainerGenerator`1.cs
index 3a098593dc..d1fbb25cb1 100644
--- a/src/Avalonia.Controls/Generators/ItemContainerGenerator`1.cs
+++ b/src/Avalonia.Controls/Generators/ItemContainerGenerator`1.cs
@@ -47,11 +47,7 @@ namespace Avalonia.Controls.Generators
         {
             var container = item as T;
 
-            if (item == null)
-            {
-                return null;
-            }
-            else if (container != null)
+            if (container != null)
             {
                 return container;
             }

From f24b6b40476207cfa8e3965a27a50b9eaa031c47 Mon Sep 17 00:00:00 2001
From: Giuseppe Lippolis <workgroupengineering@outlook.com>
Date: Fri, 25 Sep 2020 16:18:52 +0200
Subject: [PATCH 12/23] Add Test

---
 .../Generators/ItemContainerGeneratorTests.cs          | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tests/Avalonia.Controls.UnitTests/Generators/ItemContainerGeneratorTests.cs b/tests/Avalonia.Controls.UnitTests/Generators/ItemContainerGeneratorTests.cs
index ff3ad30a88..c5c7737f0d 100644
--- a/tests/Avalonia.Controls.UnitTests/Generators/ItemContainerGeneratorTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Generators/ItemContainerGeneratorTests.cs
@@ -144,6 +144,16 @@ namespace Avalonia.Controls.UnitTests.Generators
             Assert.Equal("bar", container.Content);
         }
 
+        [Fact]
+        public void Materialize_Should_Create_Containers_When_Item_Is_Null()
+        {
+            var owner = new Decorator();
+            var target = new ItemContainerGenerator<ListBoxItem>(owner, ListBoxItem.ContentProperty, null);
+            var container = (ListBoxItem)target.Materialize(0, null).ContainerControl;
+
+            Assert.True(container != null, "The containers is not materialized.");
+        }
+
         private IList<ItemContainerInfo> Materialize(
             IItemContainerGenerator generator,
             int index,

From a4c08adeb79e8188badc45b14c5b168f7cffda7e Mon Sep 17 00:00:00 2001
From: Giuseppe Lippolis <workgroupengineering@outlook.com>
Date: Sat, 26 Sep 2020 11:41:23 +0200
Subject: [PATCH 13/23] fixes Issue #3428 : ComboBox should react on
 PointerReleasedEvent instead of PointerPressedEvent

---
 src/Avalonia.Controls/ComboBox.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Controls/ComboBox.cs b/src/Avalonia.Controls/ComboBox.cs
index 27313b0b4c..02a9daee75 100644
--- a/src/Avalonia.Controls/ComboBox.cs
+++ b/src/Avalonia.Controls/ComboBox.cs
@@ -257,7 +257,7 @@ namespace Avalonia.Controls
         }
 
         /// <inheritdoc/>
-        protected override void OnPointerPressed(PointerPressedEventArgs e)
+        protected override void OnPointerReleased(PointerReleasedEventArgs e)
         {
             if (!e.Handled)
             {
@@ -276,7 +276,7 @@ namespace Avalonia.Controls
                 }
             }
 
-            base.OnPointerPressed(e);
+            base.OnPointerReleased(e);
         }
 
         /// <inheritdoc/>

From 9425ca8420cb23f63e4cc2683d17d208aa5f0ee3 Mon Sep 17 00:00:00 2001
From: Giuseppe Lippolis <workgroupengineering@outlook.com>
Date: Sat, 26 Sep 2020 12:49:40 +0200
Subject: [PATCH 14/23] fixed test

---
 tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs b/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
index 3ae91c8bba..783215fb5d 100644
--- a/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
@@ -2,7 +2,6 @@ using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Shapes;
 using Avalonia.Controls.Templates;
-using Avalonia.Input;
 using Avalonia.LogicalTree;
 using Avalonia.Media;
 using Avalonia.UnitTests;
@@ -27,6 +26,7 @@ namespace Avalonia.Controls.UnitTests
             Assert.True(target.IsDropDownOpen);
 
             _helper.Down(target);
+            _helper.Up(target);
 
             Assert.False(target.IsDropDownOpen);
         }

From c6fbe25aefdfbf29e5508853bf2f3c5ec6391141 Mon Sep 17 00:00:00 2001
From: Giuseppe Lippolis <workgroupengineering@outlook.com>
Date: Sat, 26 Sep 2020 13:01:05 +0200
Subject: [PATCH 15/23] CalendarDatePicker should react on PointerReleasedEvent
 instead of PointerPressedEvent

---
 src/Avalonia.Controls/Calendar/CalendarDatePicker.cs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/Avalonia.Controls/Calendar/CalendarDatePicker.cs b/src/Avalonia.Controls/Calendar/CalendarDatePicker.cs
index 046b55d49a..7c259f0a09 100644
--- a/src/Avalonia.Controls/Calendar/CalendarDatePicker.cs
+++ b/src/Avalonia.Controls/Calendar/CalendarDatePicker.cs
@@ -420,7 +420,7 @@ namespace Avalonia.Controls
                 _calendar.DayButtonMouseUp -= Calendar_DayButtonMouseUp;
                 _calendar.DisplayDateChanged -= Calendar_DisplayDateChanged;
                 _calendar.SelectedDatesChanged -= Calendar_SelectedDatesChanged;
-                _calendar.PointerPressed -= Calendar_PointerPressed;
+                _calendar.PointerReleased -= Calendar_PointerReleased;
                 _calendar.KeyDown -= Calendar_KeyDown;
             }
             _calendar = e.NameScope.Find<Calendar>(ElementCalendar);
@@ -435,7 +435,7 @@ namespace Avalonia.Controls
                 _calendar.DayButtonMouseUp += Calendar_DayButtonMouseUp;
                 _calendar.DisplayDateChanged += Calendar_DisplayDateChanged;
                 _calendar.SelectedDatesChanged += Calendar_SelectedDatesChanged;
-                _calendar.PointerPressed += Calendar_PointerPressed;
+                _calendar.PointerReleased += Calendar_PointerReleased;
                 _calendar.KeyDown += Calendar_KeyDown;
                 //_calendar.SizeChanged += new SizeChangedEventHandler(Calendar_SizeChanged);
                 //_calendar.IsTabStop = true;
@@ -831,9 +831,10 @@ namespace Avalonia.Controls
                 }
             }
         }
-        private void Calendar_PointerPressed(object sender, PointerPressedEventArgs e)
+        private void Calendar_PointerReleased(object sender, PointerReleasedEventArgs e)
         {
-            if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
+             
+            if (e.InitialPressMouseButton == MouseButton.Left)
             {
                 e.Handled = true;
             }

From dfe3b55de802cfef25fae53fe3e968a198f638ad Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Mon, 28 Sep 2020 19:28:24 -0400
Subject: [PATCH 16/23] DataGrid :empty-rows and :empty-columns pseudoclasses

---
 src/Avalonia.Controls.DataGrid/DataGrid.cs    | 24 +++++++++++-
 .../DataGridDataConnection.cs                 | 39 ++++++++++---------
 2 files changed, 43 insertions(+), 20 deletions(-)

diff --git a/src/Avalonia.Controls.DataGrid/DataGrid.cs b/src/Avalonia.Controls.DataGrid/DataGrid.cs
index 7c57ea3db9..5bb2763566 100644
--- a/src/Avalonia.Controls.DataGrid/DataGrid.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGrid.cs
@@ -31,7 +31,7 @@ namespace Avalonia.Controls
     /// <summary>
     /// Displays data in a customizable grid.
     /// </summary>
-    [PseudoClasses(":invalid")]
+    [PseudoClasses(":invalid", ":empty-rows", ":empty-columns")]
     public partial class DataGrid : TemplatedControl
     {
         private const string DATAGRID_elementRowsPresenterName = "PART_RowsPresenter";
@@ -711,6 +711,7 @@ namespace Avalonia.Controls
 
             DisplayData = new DataGridDisplayData(this);
             ColumnsInternal = CreateColumnsInstance();
+            ColumnsInternal.CollectionChanged += ColumnsInternal_CollectionChanged;
 
             RowHeightEstimate = DATAGRID_defaultRowHeight;
             RowDetailsHeightEstimate = 0;
@@ -727,6 +728,8 @@ namespace Avalonia.Controls
             CurrentCellCoordinates = new DataGridCellCoordinates(-1, -1);
 
             RowGroupHeaderHeightEstimate = DATAGRID_defaultRowHeight;
+
+            UpdatePseudoClasses();
         }
 
         private void SetValueNoCallback<T>(AvaloniaProperty<T> property, T value, BindingPriority priority = BindingPriority.LocalValue)
@@ -851,9 +854,27 @@ namespace Avalonia.Controls
                 // can be set when the DataGrid is not part of the visual tree
                 _measured = false;
                 InvalidateMeasure();
+
+                UpdatePseudoClasses();
             }
         }
 
+        private void ColumnsInternal_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            if (e.Action == NotifyCollectionChangedAction.Add
+                || e.Action == NotifyCollectionChangedAction.Remove
+                || e.Action == NotifyCollectionChangedAction.Reset)
+            {
+                UpdatePseudoClasses();
+            }
+        }
+
+        internal void UpdatePseudoClasses()
+        {
+            PseudoClasses.Set(":empty-columns", !ColumnsInternal.GetVisibleColumns().Any());
+            PseudoClasses.Set(":empty-rows", !DataConnection.Any());
+        }
+
         private void OnSelectedIndexChanged(AvaloniaPropertyChangedEventArgs e)
         {
             if (!_areHandlersSuspended)
@@ -1348,7 +1369,6 @@ namespace Avalonia.Controls
         internal DataGridColumnCollection ColumnsInternal
         {
             get;
-            private set;
         }
 
         internal int AnchorSlot
diff --git a/src/Avalonia.Controls.DataGrid/DataGridDataConnection.cs b/src/Avalonia.Controls.DataGrid/DataGridDataConnection.cs
index 19539bf032..a94acdec57 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridDataConnection.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridDataConnection.cs
@@ -77,24 +77,7 @@ namespace Avalonia.Controls
             private set;
         }
 
-        public int Count
-        {
-            get
-            {
-                IList list = List;
-                if (list != null)
-                {
-                    return list.Count;
-                }
-
-                if(DataSource is DataGridCollectionView cv)
-                {
-                    return cv.Count;
-                }
-
-                return DataSource?.Cast<object>().Count() ?? 0;
-            }
-        }
+        public int Count => GetCount(true);
 
         public bool DataIsPrimitive
         {
@@ -210,6 +193,24 @@ namespace Avalonia.Controls
             }
         }
 
+        internal bool Any()
+        {
+            return GetCount(false) > 0;
+        }
+
+        /// <param name="allowSlow">When "allowSlow" is false, method will not use Linq.Count() method and will return 0 or 1 instead.</param>
+        private int GetCount(bool allowSlow)
+        {
+            return DataSource switch
+            {
+                ICollection collection => collection.Count,
+                DataGridCollectionView cv => cv.Count,
+                IEnumerable enumerable when allowSlow => enumerable.Cast<object>().Count(),
+                IEnumerable enumerable when !allowSlow => enumerable.Cast<object>().Any() ? 1 : 0,
+                _ => 0
+            };
+        }
+
         /// <summary>
         /// Puts the entity into editing mode if possible
         /// </summary>
@@ -675,6 +676,8 @@ namespace Avalonia.Controls
                     }
                     break;
             }
+
+            _owner.UpdatePseudoClasses();
         }
 
         private void UpdateDataProperties()

From f56e63599d6039a990b5d26c53fa422c08340e60 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Mon, 28 Sep 2020 19:29:07 -0400
Subject: [PATCH 17/23] Handle :empty-columns pseudoclass to hide empty
 presenter with separator lines

---
 .../Themes/Fluent.xaml                        | 21 +++++++++++--------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
index 30e33c2b2d..998198cc1c 100644
--- a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
+++ b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
@@ -588,18 +588,11 @@
             <!--<DataGridColumnHeader Name="PART_TopRightCornerHeader"
                                   Grid.Column="2"
                                   Template="{StaticResource TopRightHeaderTemplate}" />-->
-            <!--<Rectangle Name="PART_ColumnHeadersAndRowsSeparator"
+            <Rectangle Name="PART_ColumnHeadersAndRowsSeparator"
                        Grid.ColumnSpan="3"
                        VerticalAlignment="Bottom"
-                       StrokeThickness="1"
                        Height="1"
-                       Fill="{DynamicResource DataGridGridLinesBrush}" />-->
-            <Border Name="PART_ColumnHeadersAndRowsSeparator"
-                    Grid.ColumnSpan="3"
-                    Height="2"
-                    VerticalAlignment="Bottom"
-                    BorderThickness="0,0,0,1"
-                    BorderBrush="{DynamicResource DataGridGridLinesBrush}" />
+                       Fill="{DynamicResource DataGridGridLinesBrush}" />
 
             <DataGridRowsPresenter Name="PART_RowsPresenter"
                                    Grid.Row="1"
@@ -642,4 +635,14 @@
       </ControlTemplate>
     </Setter>
   </Style>
+
+  <Style Selector="DataGrid:empty-columns /template/ DataGridColumnHeader#PART_TopLeftCornerHeader">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
+  <Style Selector="DataGrid:empty-columns /template/ DataGridColumnHeadersPresenter#PART_ColumnHeadersPresenter">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
+  <Style Selector="DataGrid:empty-columns /template/ Rectangle#PART_ColumnHeadersAndRowsSeparator">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
 </Styles>

From cde3c7227f0180949d2d05742dc942cc50dc1df1 Mon Sep 17 00:00:00 2001
From: Benedikt Schroeder <benedikt.schroeder@outlook.de>
Date: Wed, 30 Sep 2020 06:26:37 +0200
Subject: [PATCH 18/23] Add a test for GlyphRun.FindGlyphIndex

---
 .../Media/GlyphRunTests.cs                    | 50 +++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/tests/Avalonia.Visuals.UnitTests/Media/GlyphRunTests.cs b/tests/Avalonia.Visuals.UnitTests/Media/GlyphRunTests.cs
index 219c7ece46..58feb4714a 100644
--- a/tests/Avalonia.Visuals.UnitTests/Media/GlyphRunTests.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Media/GlyphRunTests.cs
@@ -119,6 +119,56 @@ namespace Avalonia.Visuals.UnitTests.Media
             }
         }
 
+        [InlineData(new double[] { 10, 10, 10 }, new ushort[] { 0, 0, 0 }, 0)]
+        [InlineData(new double[] { 10, 10, 10 }, new ushort[] { 0, 0, 0 }, 1)]
+        [InlineData(new double[] { 10, 10, 10, 10 }, new ushort[] { 0, 0, 0, 3 }, 0)]
+        [InlineData(new double[] { 10, 10, 10, 10 }, new ushort[] { 3, 0, 0, 0 }, 1)]
+        [InlineData(new double[] { 10, 10, 10, 10, 10 }, new ushort[] { 0, 1, 1, 1, 4 }, 0)]
+        [InlineData(new double[] { 10, 10, 10, 10, 10 }, new ushort[] { 4, 1, 1, 1, 0 }, 1)]
+        [Theory]
+        public void Should_Find_Glyph_Index(double[] advances, ushort[] clusters, int bidiLevel)
+        {
+            using (var glyphRun = CreateGlyphRun(advances, clusters, bidiLevel))
+            {
+                if (glyphRun.IsLeftToRight)
+                {
+                    for (var i = 0; i < clusters.Length; i++)
+                    {
+                        var cluster = clusters[i];
+
+                        var found = glyphRun.FindGlyphIndex(cluster);
+
+                        var expected = i;
+
+                        while (expected - 1 >= 0 && clusters[expected - 1] == cluster)
+                        {
+                            expected--;
+                        }
+
+                        Assert.Equal(expected, found);
+                    }
+                }
+                else
+                {
+                    for (var i = clusters.Length - 1; i > 0; i--)
+                    {
+                        var cluster = clusters[i];
+
+                        var found = glyphRun.FindGlyphIndex(cluster);
+
+                        var expected = i;
+
+                        while (expected + 1 < clusters.Length && clusters[expected + 1] == cluster)
+                        {
+                            expected++;
+                        }
+
+                        Assert.Equal(expected, found);
+                    }
+                }
+            }
+        }
+
         private static GlyphRun CreateGlyphRun(double[] glyphAdvances, ushort[] glyphClusters, int bidiLevel = 0)
         {
             var count = glyphAdvances.Length;

From 4f1ea8c7c1582bf963a45d6b01e96166799da273 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Wed, 30 Sep 2020 02:49:48 -0400
Subject: [PATCH 19/23] Fluent: CheckBox should respect Foreground property

---
 src/Avalonia.Themes.Fluent/CheckBox.xaml | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/src/Avalonia.Themes.Fluent/CheckBox.xaml b/src/Avalonia.Themes.Fluent/CheckBox.xaml
index 73c44c02ab..c2ef764abe 100644
--- a/src/Avalonia.Themes.Fluent/CheckBox.xaml
+++ b/src/Avalonia.Themes.Fluent/CheckBox.xaml
@@ -1,12 +1,11 @@
 <Styles xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Design.PreviewWith>
     <Border Padding="20">
-      <CheckBox IsThreeState="True" IsChecked="True" />
+      <CheckBox IsThreeState="True" IsChecked="True" Content="Content" Foreground="Gold" />
     </Border>
   </Design.PreviewWith>
   <Style Selector="CheckBox">
     <Setter Property="Background" Value="{DynamicResource CheckBoxBackgroundUnchecked}" />
-    <Setter Property="Foreground" Value="{DynamicResource CheckBoxForegroundUnchecked}" />
     <Setter Property="BorderBrush" Value="{DynamicResource CheckBoxBorderBrushUnchecked}" />
     <Setter Property="Padding" Value="8,0,0,0" />
     <Setter Property="HorizontalAlignment" Value="Left" />
@@ -55,8 +54,8 @@
   </Style>
 
   <!-- Unchecked Normal State -->
-  <Style Selector="CheckBox /template/ ContentPresenter#ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource CheckBoxForegroundUnchecked}" />
+  <Style Selector="CheckBox">
+    <Setter Property="Foreground" Value="{DynamicResource CheckBoxForegroundUnchecked}" />
   </Style>
 
   <Style Selector="CheckBox /template/ Border#PART_Border">
@@ -133,8 +132,8 @@
 
 
   <!-- Checked Normal State -->
-  <Style Selector="CheckBox:checked /template/ ContentPresenter#ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource CheckBoxForegroundChecked}" />
+  <Style Selector="CheckBox:checked">
+    <Setter Property="Foreground" Value="{DynamicResource CheckBoxForegroundChecked}" />
   </Style>
 
   <Style Selector="CheckBox:checked /template/ Border#PART_Border">
@@ -213,8 +212,8 @@
 
 
   <!-- Indeterminate Normal State -->
-  <Style Selector="CheckBox:indeterminate /template/ ContentPresenter#ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource CheckBoxForegroundIndeterminate}" />
+  <Style Selector="CheckBox:indeterminate">
+    <Setter Property="Foreground" Value="{DynamicResource CheckBoxForegroundIndeterminate}" />
   </Style>
 
   <Style Selector="CheckBox:indeterminate /template/ Border#PART_Border">

From 4b4d9816f9ea23868231923e5f80e31806a34232 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Wed, 30 Sep 2020 03:01:18 -0400
Subject: [PATCH 20/23] Fluent: CheckBox should respect Background and
 BorderBrush

---
 src/Avalonia.Themes.Fluent/CheckBox.xaml | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/Avalonia.Themes.Fluent/CheckBox.xaml b/src/Avalonia.Themes.Fluent/CheckBox.xaml
index c2ef764abe..678ae5c5a3 100644
--- a/src/Avalonia.Themes.Fluent/CheckBox.xaml
+++ b/src/Avalonia.Themes.Fluent/CheckBox.xaml
@@ -5,8 +5,6 @@
     </Border>
   </Design.PreviewWith>
   <Style Selector="CheckBox">
-    <Setter Property="Background" Value="{DynamicResource CheckBoxBackgroundUnchecked}" />
-    <Setter Property="BorderBrush" Value="{DynamicResource CheckBoxBorderBrushUnchecked}" />
     <Setter Property="Padding" Value="8,0,0,0" />
     <Setter Property="HorizontalAlignment" Value="Left" />
     <Setter Property="VerticalAlignment" Value="Center" />
@@ -20,10 +18,12 @@
     <Setter Property="Template">
       <ControlTemplate>
         <Grid x:Name="RootGrid" ColumnDefinitions="20,*">
-          <Border x:Name="PART_Border" Background="{TemplateBinding Background}"
-                       BorderBrush="{TemplateBinding BorderBrush}"
-                       BorderThickness="{TemplateBinding BorderThickness}"
-                        CornerRadius="{DynamicResource ControlCornerRadius}" />
+          <Border x:Name="PART_Border"
+                  Grid.ColumnSpan="2"
+                  Background="{TemplateBinding Background}"
+                  BorderBrush="{TemplateBinding BorderBrush}"
+                  BorderThickness="{TemplateBinding BorderThickness}"
+                  CornerRadius="{DynamicResource ControlCornerRadius}" />
 
           <Grid VerticalAlignment="Top" Height="32">
             <Border x:Name="NormalRectangle"
@@ -58,7 +58,7 @@
     <Setter Property="Foreground" Value="{DynamicResource CheckBoxForegroundUnchecked}" />
   </Style>
 
-  <Style Selector="CheckBox /template/ Border#PART_Border">
+  <Style Selector="CheckBox">
     <Setter Property="Background" Value="{DynamicResource CheckBoxBackgroundUnchecked}" />
     <Setter Property="BorderBrush" Value="{DynamicResource CheckBoxBorderBrushUnchecked}" />
   </Style>
@@ -136,7 +136,7 @@
     <Setter Property="Foreground" Value="{DynamicResource CheckBoxForegroundChecked}" />
   </Style>
 
-  <Style Selector="CheckBox:checked /template/ Border#PART_Border">
+  <Style Selector="CheckBox:checked">
     <Setter Property="Background" Value="{DynamicResource CheckBoxBackgroundChecked}" />
     <Setter Property="BorderBrush" Value="{DynamicResource CheckBoxBorderBrushChecked}" />
   </Style>
@@ -216,7 +216,7 @@
     <Setter Property="Foreground" Value="{DynamicResource CheckBoxForegroundIndeterminate}" />
   </Style>
 
-  <Style Selector="CheckBox:indeterminate /template/ Border#PART_Border">
+  <Style Selector="CheckBox:indeterminate">
     <Setter Property="Background" Value="{DynamicResource CheckBoxBackgroundIndeterminate}" />
     <Setter Property="BorderBrush" Value="{DynamicResource CheckBoxBorderBrushIndeterminate}" />
   </Style>

From 21b0a468fb44d29d3b223a4dc2cd63ebf5e6ef0e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dariusz=20Komosi=C5=84ski?= <darek.komosinski@gmail.com>
Date: Wed, 30 Sep 2020 12:35:43 +0200
Subject: [PATCH 21/23] Parse key splines using invariant culture.

---
 src/Avalonia.Animation/KeySplineTypeConverter.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Avalonia.Animation/KeySplineTypeConverter.cs b/src/Avalonia.Animation/KeySplineTypeConverter.cs
index cd7427a37d..b026206e5f 100644
--- a/src/Avalonia.Animation/KeySplineTypeConverter.cs
+++ b/src/Avalonia.Animation/KeySplineTypeConverter.cs
@@ -19,7 +19,7 @@ namespace Avalonia.Animation
 
         public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
         {
-            return KeySpline.Parse((string)value, culture);
+            return KeySpline.Parse((string)value, CultureInfo.InvariantCulture);
         }
     }
 }

From d4cb11be47618e14089cdb5fa6779011256a80c6 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Wed, 30 Sep 2020 15:27:49 +0200
Subject: [PATCH 22/23] Bind ScrollViewer scrollbar visibility properties.

And disable the horizontal scrollbar on the default theme (this was already being done in fluent theme).

Fixes #4768.
---
 src/Avalonia.Themes.Default/ComboBox.xaml | 4 +++-
 src/Avalonia.Themes.Fluent/ComboBox.xaml  | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Themes.Default/ComboBox.xaml b/src/Avalonia.Themes.Default/ComboBox.xaml
index cced76e850..67151731a8 100644
--- a/src/Avalonia.Themes.Default/ComboBox.xaml
+++ b/src/Avalonia.Themes.Default/ComboBox.xaml
@@ -26,6 +26,7 @@
     <Setter Property="Padding" Value="4" />
     <Setter Property="MinHeight" Value="20" />
     <Setter Property="PlaceholderForeground" Value="{DynamicResource ThemeForegroundBrush}" />
+    <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled" />
     <Setter Property="Template">
       <ControlTemplate>
         <Border Name="border"
@@ -69,7 +70,8 @@
                    IsLightDismissEnabled="True">
               <Border BorderBrush="{DynamicResource ThemeBorderMidBrush}"
                       BorderThickness="1">
-                <ScrollViewer>
+                <ScrollViewer HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
+                              VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}">
                   <ItemsPresenter Name="PART_ItemsPresenter"
                                   Items="{TemplateBinding Items}"
                                   ItemsPanel="{TemplateBinding ItemsPanel}"
diff --git a/src/Avalonia.Themes.Fluent/ComboBox.xaml b/src/Avalonia.Themes.Fluent/ComboBox.xaml
index a89b18b272..f77f1b582b 100644
--- a/src/Avalonia.Themes.Fluent/ComboBox.xaml
+++ b/src/Avalonia.Themes.Fluent/ComboBox.xaml
@@ -133,7 +133,8 @@
                     Padding="{DynamicResource ComboBoxDropdownBorderPadding}"
                     HorizontalAlignment="Stretch"
                     CornerRadius="{DynamicResource OverlayCornerRadius}">
-              <ScrollViewer>
+              <ScrollViewer HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
+                            VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}">
                 <ItemsPresenter Name="PART_ItemsPresenter"
                                 Items="{TemplateBinding Items}"
                                 Margin="{DynamicResource ComboBoxDropdownContentMargin}"

From ef1e5b81d88ff46d1f8fa58fc94773817c949b46 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Fri, 2 Oct 2020 07:21:47 -0400
Subject: [PATCH 23/23] Fluent: fix duplicated backgrounds on ListBoxItem

---
 src/Avalonia.Themes.Fluent/ListBoxItem.xaml | 85 ++++++++++-----------
 1 file changed, 41 insertions(+), 44 deletions(-)

diff --git a/src/Avalonia.Themes.Fluent/ListBoxItem.xaml b/src/Avalonia.Themes.Fluent/ListBoxItem.xaml
index 430d3c5468..7715ddf1f1 100644
--- a/src/Avalonia.Themes.Fluent/ListBoxItem.xaml
+++ b/src/Avalonia.Themes.Fluent/ListBoxItem.xaml
@@ -1,9 +1,13 @@
-<Styles xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Design.PreviewWith>
     <Border Padding="0">
       <ListBox>
         <ListBoxItem IsEnabled="False">Disabled</ListBoxItem>
-        <ListBoxItem>Test</ListBoxItem>
+        <ListBoxItem Background="#66000000"
+                     Padding="20">
+          Test
+        </ListBoxItem>
         <ListBoxItem>Test</ListBoxItem>
       </ListBox>
     </Border>
@@ -17,11 +21,7 @@
     <Setter Property="HorizontalContentAlignment" Value="Left" />
     <Setter Property="Template">
       <ControlTemplate>
-        <Border x:Name="LayoutRoot" Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}">
-          <Panel>
-
-            <Rectangle x:Name="PressedBackground" IsHitTestVisible="False"  />
-            <ContentPresenter Name="PART_ContentPresenter"
+        <ContentPresenter Name="PART_ContentPresenter"
                           Background="{TemplateBinding Background}"
                           BorderBrush="{TemplateBinding BorderBrush}"
                           BorderThickness="{TemplateBinding BorderThickness}"
@@ -29,69 +29,66 @@
                           Content="{TemplateBinding Content}"
                           Padding="{TemplateBinding Padding}"
                           VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
-                          HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"/>
-
-          </Panel>
-        </Border>
+                          HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" />
       </ControlTemplate>
     </Setter>
   </Style>
 
-  <Style Selector="ListBoxItem /template/ ContentPresenter">
+  <Style Selector="ListBoxItem /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="TextBlock.FontWeight" Value="Normal" />
     <Setter Property="TextBlock.FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
   </Style>
 
-  <!-- Disabled State -->  
-  <Style Selector="ListBoxItem:disabled /template/ ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlDisabledBaseMediumLowBrush}"/>
+  <!--  Disabled State  -->
+  <Style Selector="ListBoxItem:disabled /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlDisabledBaseMediumLowBrush}" />
   </Style>
-  
-  <!-- PointerOver State -->
-  <Style Selector="ListBoxItem:pointerover /template/ Rectangle#PressedBackground">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListLowBrush}"/>
+
+  <!--  PointerOver State  -->
+  <Style Selector="ListBoxItem:pointerover /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource SystemControlHighlightListLowBrush}" />
   </Style>
-  <Style Selector="ListBoxItem:pointerover /template/ ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}"/>
+  <Style Selector="ListBoxItem:pointerover /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}" />
   </Style>
 
-  <!-- Pressed State -->
-  <Style Selector="ListBoxItem:pressed /template/ Rectangle#PressedBackground">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListMediumBrush}"/>
+  <!--  Pressed State  -->
+  <Style Selector="ListBoxItem:pressed /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource SystemControlHighlightListMediumBrush}" />
   </Style>
   <Style Selector="ListBoxItem:pressed /template/ ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}" />
   </Style>
 
-  <!-- Selected State -->
-  <Style Selector="ListBoxItem:selected /template/ Rectangle#PressedBackground">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListAccentLowBrush}"/>
+  <!--  Selected State  -->
+  <Style Selector="ListBoxItem:selected /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource SystemControlHighlightListAccentLowBrush}" />
   </Style>
   <Style Selector="ListBoxItem:selected /template/ ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}" />
   </Style>
-  
-  <!-- Selected Unfocused State -->
-  <Style Selector="ListBoxItem:selected:not(:focus) /template/ Rectangle#PressedBackground">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListAccentLowBrush}"/>
+
+  <!--  Selected Unfocused State  -->
+  <Style Selector="ListBoxItem:selected:not(:focus) /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource SystemControlHighlightListAccentLowBrush}" />
   </Style>
-  <Style Selector="ListBoxItem:selected:not(:focus) /template/ ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}"/>
+  <Style Selector="ListBoxItem:selected:not(:focus) /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}" />
   </Style>
 
-  <!-- Selected PointerOver State -->
-  <Style Selector="ListBoxItem:selected:pointerover /template/ Rectangle#PressedBackground">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListAccentMediumBrush}"/>
+  <!--  Selected PointerOver State  -->
+  <Style Selector="ListBoxItem:selected:pointerover /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource SystemControlHighlightListAccentMediumBrush}" />
   </Style>
   <Style Selector="ListBoxItem:selected:pointerover /template/ ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}" />
   </Style>
 
-<!-- Selected Pressed State -->
-  <Style Selector="ListBoxItem:selected:pressed /template/ Rectangle#PressedBackground">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListAccentHighBrush}"/>
+  <!--  Selected Pressed State  -->
+  <Style Selector="ListBoxItem:selected:pressed /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource SystemControlHighlightListAccentHighBrush}" />
   </Style>
-  <Style Selector="ListBoxItem:selected:pressed /template/ ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}"/>
+  <Style Selector="ListBoxItem:selected:pressed /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}" />
   </Style>
 </Styles>