Merge branch 'master' into fix/radial-gradient-brush

samples/ControlCatalog/App.xaml.cs

@@ -81,7 +81,7 @@ namespace ControlCatalog
 
         public override void Initialize()
         {
-            Styles.Insert(0, FluentDark);
+            Styles.Insert(0, FluentLight);
 
             AvaloniaXamlLoader.Load(this);
         }

samples/ControlCatalog/MainView.xaml

@@ -77,8 +77,8 @@
             <ComboBoxItem>Full Decorations</ComboBoxItem>
           </ComboBox>
           <ComboBox x:Name="Themes" SelectedIndex="0">
-            <ComboBoxItem>Fluent - Dark</ComboBoxItem>
             <ComboBoxItem>Fluent - Light</ComboBoxItem>
+            <ComboBoxItem>Fluent - Dark</ComboBoxItem>
             <ComboBoxItem>Simple - Light</ComboBoxItem>
             <ComboBoxItem>Simple - Dark</ComboBoxItem>
           </ComboBox>

samples/ControlCatalog/MainView.xaml.cs

@@ -38,10 +38,10 @@ namespace ControlCatalog
                 switch (themes.SelectedIndex)
                 {
                     case 0:
-                        Application.Current.Styles[0] = App.FluentDark;
+                        Application.Current.Styles[0] = App.FluentLight;
                         break;
                     case 1:
-                        Application.Current.Styles[0] = App.FluentLight;
+                        Application.Current.Styles[0] = App.FluentDark;
                         break;
                     case 2:
                         Application.Current.Styles[0] = App.DefaultLight;

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);
         }
     }
 }

src/Avalonia.Base/AvaloniaObject.cs

@@ -113,16 +113,8 @@ namespace Avalonia
         /// <param name="binding">The binding information.</param>
         public IBinding this[IndexerDescriptor binding]
         {
-            get
+            get { return new IndexerBinding(this, binding.Property, binding.Mode); }
-            {
+            set { this.Bind(binding.Property, value); }
-                return new IndexerBinding(this, binding.Property, binding.Mode);
-            }
-
-            set
-            {
-                var sourceBinding = value as IBinding;
-                this.Bind(binding.Property, sourceBinding);
-            }
         }
 
         public bool CheckAccess() => Dispatcher.UIThread.CheckAccess();

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)));
                 }
             }
         }

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

src/Avalonia.Controls.DataGrid/DataGridDataConnection.cs

@@ -77,24 +77,7 @@ namespace Avalonia.Controls
             private set;
         }
 
-        public int Count
+        public int Count => GetCount(true);
-        {
-            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 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()

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}" />-->
+                       Fill="{DynamicResource DataGridGridLinesBrush}" />
-            <Border Name="PART_ColumnHeadersAndRowsSeparator"
-                    Grid.ColumnSpan="3"
-                    Height="2"
-                    VerticalAlignment="Bottom"
-                    BorderThickness="0,0,0,1"
-                    BorderBrush="{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>

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;
             }

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/>

src/Avalonia.Controls/Generators/ItemContainerGenerator`1.cs

@@ -47,11 +47,7 @@ namespace Avalonia.Controls.Generators
         {
             var container = item as T;
 
-            if (item == null)
+            if (container != null)
-            {
-                return null;
-            }
-            else if (container != null)
             {
                 return container;
             }

src/Avalonia.Controls/Presenters/TextPresenter.cs

@@ -77,7 +77,8 @@ namespace Avalonia.Controls.Presenters
 
         static TextPresenter()
         {
-            AffectsRender<TextPresenter>(SelectionBrushProperty);
+            AffectsRender<TextPresenter>(SelectionBrushProperty, TextBlock.ForegroundProperty, 
+                                         SelectionForegroundBrushProperty, CaretBrushProperty);
             AffectsMeasure<TextPresenter>(TextProperty, PasswordCharProperty, RevealPasswordProperty, 
                 TextAlignmentProperty, TextWrappingProperty, TextBlock.FontSizeProperty,
                 TextBlock.FontStyleProperty, TextBlock.FontWeightProperty, TextBlock.FontFamilyProperty);

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(
+                _isOpenRequested = true;
-                    "Attempted to open a popup not attached to a TopLevel");
+                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())

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}"

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}"

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

@@ -12,7 +12,7 @@
     <Color x:Key="SystemColorHotlightColor">#FF0066CC</Color>
     <Color x:Key="SystemColorWindowColor">#FFFFFFFF</Color>
     <Color x:Key="SystemColorWindowTextColor">#FF000000</Color>
-    <FontFamily x:Key="ContentControlThemeFontFamily">avares://Avalonia.Themes.Fluent/Assets#Roboto</FontFamily>
+    <FontFamily x:Key="ContentControlThemeFontFamily">avares://Avalonia.Themes.Fluent/Assets#Inter</FontFamily>
     <sys:Double x:Key="ControlContentThemeFontSize">14</sys:Double>
 
     <SolidColorBrush x:Key="SystemControlTransparentBrush" Color="Transparent" />

src/Avalonia.Themes.Fluent/CheckBox.xaml

@@ -1,13 +1,10 @@
 <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" />
     <Setter Property="VerticalAlignment" Value="Center" />
@@ -21,10 +18,12 @@
     <Setter Property="Template">
       <ControlTemplate>
         <Grid x:Name="RootGrid" ColumnDefinitions="20,*">
-          <Border x:Name="PART_Border" Background="{TemplateBinding Background}"
+          <Border x:Name="PART_Border"
-                       BorderBrush="{TemplateBinding BorderBrush}"
+                  Grid.ColumnSpan="2"
-                       BorderThickness="{TemplateBinding BorderThickness}"
+                  Background="{TemplateBinding Background}"
-                        CornerRadius="{DynamicResource ControlCornerRadius}" />
+                  BorderBrush="{TemplateBinding BorderBrush}"
+                  BorderThickness="{TemplateBinding BorderThickness}"
+                  CornerRadius="{DynamicResource ControlCornerRadius}" />
 
           <Grid VerticalAlignment="Top" Height="32">
             <Border x:Name="NormalRectangle"
@@ -55,11 +54,11 @@
   </Style>
 
   <!-- Unchecked Normal State -->
-  <Style Selector="CheckBox /template/ ContentPresenter#ContentPresenter">
+  <Style Selector="CheckBox">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource CheckBoxForegroundUnchecked}" />
+    <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>
@@ -133,11 +132,11 @@
 
 
   <!-- Checked Normal State -->
-  <Style Selector="CheckBox:checked /template/ ContentPresenter#ContentPresenter">
+  <Style Selector="CheckBox:checked">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource CheckBoxForegroundChecked}" />
+    <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>
@@ -213,11 +212,11 @@
 
 
   <!-- Indeterminate Normal State -->
-  <Style Selector="CheckBox:indeterminate /template/ ContentPresenter#ContentPresenter">
+  <Style Selector="CheckBox:indeterminate">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource CheckBoxForegroundIndeterminate}" />
+    <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>

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}"

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}"

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}">
+        <ContentPresenter Name="PART_ContentPresenter"
-          <Panel>
-
-            <Rectangle x:Name="PressedBackground" IsHitTestVisible="False"  />
-            <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}"/>
+                          HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" />
-
-          </Panel>
-        </Border>
       </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 -->  
+  <!--  Disabled State  -->
-  <Style Selector="ListBoxItem:disabled /template/ ContentPresenter">
+  <Style Selector="ListBoxItem:disabled /template/ ContentPresenter#PART_ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlDisabledBaseMediumLowBrush}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlDisabledBaseMediumLowBrush}" />
   </Style>
-  
+
-  <!-- PointerOver State -->
+  <!--  PointerOver State  -->
-  <Style Selector="ListBoxItem:pointerover /template/ Rectangle#PressedBackground">
+  <Style Selector="ListBoxItem:pointerover /template/ ContentPresenter#PART_ContentPresenter">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListLowBrush}"/>
+    <Setter Property="Background" Value="{DynamicResource SystemControlHighlightListLowBrush}" />
   </Style>
-  <Style Selector="ListBoxItem:pointerover /template/ ContentPresenter">
+  <Style Selector="ListBoxItem:pointerover /template/ ContentPresenter#PART_ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}" />
   </Style>
 
-  <!-- Pressed State -->
+  <!--  Pressed State  -->
-  <Style Selector="ListBoxItem:pressed /template/ Rectangle#PressedBackground">
+  <Style Selector="ListBoxItem:pressed /template/ ContentPresenter#PART_ContentPresenter">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListMediumBrush}"/>
+    <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 -->
+  <!--  Selected State  -->
-  <Style Selector="ListBoxItem:selected /template/ Rectangle#PressedBackground">
+  <Style Selector="ListBoxItem:selected /template/ ContentPresenter#PART_ContentPresenter">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListAccentLowBrush}"/>
+    <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 -->
+  <!--  Selected Unfocused State  -->
-  <Style Selector="ListBoxItem:selected:not(:focus) /template/ Rectangle#PressedBackground">
+  <Style Selector="ListBoxItem:selected:not(:focus) /template/ ContentPresenter#PART_ContentPresenter">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListAccentLowBrush}"/>
+    <Setter Property="Background" Value="{DynamicResource SystemControlHighlightListAccentLowBrush}" />
   </Style>
-  <Style Selector="ListBoxItem:selected:not(:focus) /template/ ContentPresenter">
+  <Style Selector="ListBoxItem:selected:not(:focus) /template/ ContentPresenter#PART_ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}" />
   </Style>
 
-  <!-- Selected PointerOver State -->
+  <!--  Selected PointerOver State  -->
-  <Style Selector="ListBoxItem:selected:pointerover /template/ Rectangle#PressedBackground">
+  <Style Selector="ListBoxItem:selected:pointerover /template/ ContentPresenter#PART_ContentPresenter">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListAccentMediumBrush}"/>
+    <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 -->
+  <!--  Selected Pressed State  -->
-  <Style Selector="ListBoxItem:selected:pressed /template/ Rectangle#PressedBackground">
+  <Style Selector="ListBoxItem:selected:pressed /template/ ContentPresenter#PART_ContentPresenter">
-    <Setter Property="Fill" Value="{DynamicResource SystemControlHighlightListAccentHighBrush}"/>
+    <Setter Property="Background" Value="{DynamicResource SystemControlHighlightListAccentHighBrush}" />
   </Style>
-  <Style Selector="ListBoxItem:selected:pressed /template/ ContentPresenter">
+  <Style Selector="ListBoxItem:selected:pressed /template/ ContentPresenter#PART_ContentPresenter">
-    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SystemControlHighlightAltBaseHighBrush}" />
   </Style>
 </Styles>

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}"

src/Avalonia.Themes.Fluent/ScrollViewer.xaml

@@ -1,5 +1,21 @@
-<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">
 
+  <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" />
@@ -66,4 +82,78 @@
     <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>
+            <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"
+                        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>
+            <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}"
+                                  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 > Viewbox > Path">
+    <Setter Property="Fill" Value="{DynamicResource ScrollBarButtonArrowForeground}" />
+  </Style>
+
+  <Style Selector="ScrollViewer.menuscroller /template/ RepeatButton:pointerover > Viewbox > Path">
+    <Setter Property="Fill" Value="{DynamicResource ScrollBarButtonArrowForegroundPointerOver}" />
+  </Style>
+
 </Styles>

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);

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);
         }

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,

tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs

@@ -21,7 +21,50 @@ 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()
+        {
+            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()
         {