Merge branch 'master' into fixes/macCaretPosition

.ncrunch/SafeAreaDemo.Android.v3.ncrunchproject

@@ -0,0 +1,5 @@
+<ProjectConfiguration>
+  <Settings>
+    <IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely>
+  </Settings>
+</ProjectConfiguration>

.ncrunch/SafeAreaDemo.Desktop.v3.ncrunchproject

@@ -0,0 +1,5 @@
+<ProjectConfiguration>
+  <Settings>
+    <IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely>
+  </Settings>
+</ProjectConfiguration>

.ncrunch/SafeAreaDemo.iOS.v3.ncrunchproject

@@ -0,0 +1,5 @@
+<ProjectConfiguration>
+  <Settings>
+    <IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely>
+  </Settings>
+</ProjectConfiguration>

.ncrunch/SafeAreaDemo.v3.ncrunchproject

@@ -0,0 +1,5 @@
+<ProjectConfiguration>
+  <Settings>
+    <IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely>
+  </Settings>
+</ProjectConfiguration>

samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml.cs

@@ -114,7 +114,7 @@ namespace ControlCatalog.Pages
 
             foreach (AutoCompleteBox box in GetAllAutoCompleteBox().Where(x => x.Name != "CustomAutocompleteBox"))
             {
-                box.Items = States;
+                box.ItemsSource = States;
             }
 
             var converter = new FuncMultiValueConverter<string, string>(parts =>
@@ -132,7 +132,7 @@ namespace ControlCatalog.Pages
             asyncBox.AsyncPopulator = PopulateAsync;
 
             var customAutocompleteBox = this.Get<AutoCompleteBox>("CustomAutocompleteBox");
-            customAutocompleteBox.Items = Sentences.SelectMany(x => x);
+            customAutocompleteBox.ItemsSource = Sentences.SelectMany(x => x);
             customAutocompleteBox.TextFilter = LastWordContains;
             customAutocompleteBox.TextSelector = AppendWord;
         }

samples/ControlCatalog/Pages/ContextFlyoutPage.xaml

@@ -67,7 +67,7 @@
           </Style>
         </Border.Styles>
         <Border.ContextFlyout>
-          <MenuFlyout Items="{Binding MenuItems}" />
+          <MenuFlyout ItemsSource="{Binding MenuItems}" />
         </Border.ContextFlyout>
         <TextBlock Text="Dynamically Generated"/>
       </Border>

samples/ControlCatalog/Pages/DataGridPage.xaml

@@ -94,7 +94,7 @@
         <Grid RowDefinitions="*,Auto">
           <!-- Example of columns inheriting the data type from the Items source -->
           <DataGrid Name="dataGridEdit" Margin="12" Grid.Row="0"
-                    Items="{Binding DataGrid3Source}">
+                    ItemsSource="{Binding DataGrid3Source}">
             <DataGrid.Columns>
               <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}" />

samples/ControlCatalog/Pages/DataGridPage.xaml.cs

@@ -36,7 +36,7 @@ namespace ControlCatalog.Pages
                     collectionView1.SortDescriptions.Add(dataGridSortDescription);
                 }
             };
-            dg1.Items = collectionView1;
+            dg1.ItemsSource = collectionView1;
 
             var dg2 = this.Get<DataGrid>("dataGridGrouping");
             dg2.IsReadOnly = true;
@@ -44,7 +44,7 @@ namespace ControlCatalog.Pages
             var collectionView2 = new DataGridCollectionView(Countries.All);
             collectionView2.GroupDescriptions.Add(new DataGridPathGroupDescription("Region"));
 
-            dg2.Items = collectionView2;
+            dg2.ItemsSource = collectionView2;
 
             var dg3 = this.Get<DataGrid>("dataGridEdit");
             dg3.IsReadOnly = false;

samples/ControlCatalog/Pages/DialogsPage.xaml

@@ -45,7 +45,7 @@
     </Expander>
 
     <AutoCompleteBox x:Name="CurrentFolderBox" Watermark="Write full path/uri or well known folder name">
-      <AutoCompleteBox.Items>
+      <AutoCompleteBox.ItemsSource>
         <generic:List x:TypeArguments="storage:WellKnownFolder">
           <storage:WellKnownFolder>Desktop</storage:WellKnownFolder>
           <storage:WellKnownFolder>Documents</storage:WellKnownFolder>
@@ -54,7 +54,7 @@
           <storage:WellKnownFolder>Videos</storage:WellKnownFolder>
           <storage:WellKnownFolder>Music</storage:WellKnownFolder>
         </generic:List>
-      </AutoCompleteBox.Items>
+      </AutoCompleteBox.ItemsSource>
     </AutoCompleteBox>
     
     <TextBlock x:Name="PickerLastResultsVisible"

samples/ControlCatalog/Pages/ItemsRepeaterPage.xaml

@@ -66,7 +66,7 @@
       <ScrollViewer Name="scroller"
                     HorizontalScrollBarVisibility="Auto"
                     VerticalScrollBarVisibility="Auto">
-        <ItemsRepeater Name="repeater" Background="Transparent" Items="{Binding Items}"
+        <ItemsRepeater Name="repeater" Background="Transparent" ItemsSource="{Binding Items}"
                        ItemTemplate="{StaticResource elementFactory}"/>
       </ScrollViewer>
     </Border>

src/Avalonia.Controls.DataGrid/DataGrid.cs

@@ -152,8 +152,6 @@ namespace Avalonia.Controls
         private double _verticalOffset;
         private byte _verticalScrollChangesIgnored;
 
-        private IEnumerable _items;
-
         public event EventHandler<ScrollEventArgs> HorizontalScroll;
         public event EventHandler<ScrollEventArgs> VerticalScroll;
 
@@ -652,21 +650,18 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// Identifies the ItemsSource dependency property.
+        /// Identifies the ItemsSource property.
         /// </summary>
-        public static readonly DirectProperty<DataGrid, IEnumerable> ItemsProperty =
+        public static readonly StyledProperty<IEnumerable> ItemsSourceProperty =
-            AvaloniaProperty.RegisterDirect<DataGrid, IEnumerable>(
+            AvaloniaProperty.Register<DataGrid, IEnumerable>(nameof(ItemsSource));
-                nameof(Items),
-                o => o.Items,
-                (o, v) => o.Items = v);
 
         /// <summary>
         /// Gets or sets a collection that is used to generate the content of the control.
         /// </summary>
-        public IEnumerable Items
+        public IEnumerable ItemsSource
         {
-            get { return _items; }
+            get => GetValue(ItemsSourceProperty);
-            set { SetAndRaise(ItemsProperty, ref _items, value); }
+            set => SetValue(ItemsSourceProperty, value);
         }
 
         public static readonly StyledProperty<bool> AreRowDetailsFrozenProperty =
@@ -713,7 +708,7 @@ namespace Avalonia.Controls
                 HorizontalScrollBarVisibilityProperty,
                 VerticalScrollBarVisibilityProperty);
 
-            ItemsProperty.Changed.AddClassHandler<DataGrid>((x, e) => x.OnItemsPropertyChanged(e));
+            ItemsSourceProperty.Changed.AddClassHandler<DataGrid>((x, e) => x.OnItemsSourcePropertyChanged(e));
             CanUserResizeColumnsProperty.Changed.AddClassHandler<DataGrid>((x, e) => x.OnCanUserResizeColumnsChanged(e));
             ColumnWidthProperty.Changed.AddClassHandler<DataGrid>((x, e) => x.OnColumnWidthChanged(e));
             FrozenColumnCountProperty.Changed.AddClassHandler<DataGrid>((x, e) => x.OnFrozenColumnCountChanged(e));
@@ -816,10 +811,10 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// ItemsProperty property changed handler.
+        /// ItemsSourceProperty property changed handler.
         /// </summary>
         /// <param name="e">The event arguments.</param>
-        private void OnItemsPropertyChanged(AvaloniaPropertyChangedEventArgs e)
+        private void OnItemsSourcePropertyChanged(AvaloniaPropertyChangedEventArgs e)
         {
             if (!_areHandlersSuspended)
             {
@@ -830,7 +825,7 @@ namespace Avalonia.Controls
 
                 if (LoadingOrUnloadingRow)
                 {
-                    SetValueNoCallback(ItemsProperty, oldValue);
+                    SetValueNoCallback(ItemsSourceProperty, oldValue);
                     throw DataGridError.DataGrid.CannotChangeItemsWhenLoadingRows();
                 }
 
@@ -1855,7 +1850,7 @@ namespace Avalonia.Controls
         {
             get
             {
-                if (CurrentSlot == -1 || Items == null || RowGroupHeadersTable.Contains(CurrentSlot))
+                if (CurrentSlot == -1 || ItemsSource == null || RowGroupHeadersTable.Contains(CurrentSlot))
                 {
                     return null;
                 }

src/Avalonia.Controls.DataGrid/DataGridBoundColumn.cs

@@ -25,7 +25,7 @@ namespace Avalonia.Controls
         /// </summary>
         //TODO Binding
         [AssignBinding]
-        [InheritDataTypeFromItems(nameof(DataGrid.Items), AncestorType = typeof(DataGrid))]
+        [InheritDataTypeFromItems(nameof(DataGrid.ItemsSource), AncestorType = typeof(DataGrid))]
         public virtual IBinding Binding
         {
             get

src/Avalonia.Controls.DataGrid/DataGridDataConnection.cs

@@ -122,9 +122,9 @@ namespace Avalonia.Controls
                 // We need to use the raw ItemsSource as opposed to DataSource because DataSource
                 // may be the ItemsSource wrapped in a collection view, in which case we wouldn't
                 // be able to take T to be the type if we're given IEnumerable<T>
-                if (_dataType == null && _owner.Items != null)
+                if (_dataType == null && _owner.ItemsSource != null)
                 {
-                    _dataType = _owner.Items.GetItemType();
+                    _dataType = _owner.ItemsSource.GetItemType();
                 }
                 return _dataType;
             }

src/Avalonia.Controls.DataGrid/DataGridTemplateColumn.cs

@@ -24,7 +24,7 @@ namespace Avalonia.Controls
                 (o, v) => o.CellTemplate = v);
 
         [Content]
-        [InheritDataTypeFromItems(nameof(DataGrid.Items), AncestorType = typeof(DataGrid))]
+        [InheritDataTypeFromItems(nameof(DataGrid.ItemsSource), AncestorType = typeof(DataGrid))]
         public IDataTemplate CellTemplate
         {
             get { return _cellTemplate; }
@@ -51,7 +51,7 @@ namespace Avalonia.Controls
         /// <remarks>
         /// If this property is <see langword="null"/> the column is read-only.
         /// </remarks>
-        [InheritDataTypeFromItems(nameof(DataGrid.Items), AncestorType = typeof(DataGrid))]
+        [InheritDataTypeFromItems(nameof(DataGrid.ItemsSource), AncestorType = typeof(DataGrid))]
         public IDataTemplate CellEditingTemplate
         {
             get => _cellEditingCellTemplate;

src/Avalonia.Controls.ItemsRepeater/Controls/ItemsRepeater.cs

@@ -36,13 +36,13 @@ namespace Avalonia.Controls
             ItemsControl.ItemTemplateProperty.AddOwner<ItemsRepeater>();
 
         /// <summary>
-        /// Defines the <see cref="Items"/> property.
+        /// Defines the <see cref="ItemsSource"/> property.
         /// </summary>
-        public static readonly DirectProperty<ItemsRepeater, IEnumerable?> ItemsProperty =
+        public static readonly DirectProperty<ItemsRepeater, IEnumerable?> ItemsSourceProperty =
             AvaloniaProperty.RegisterDirect<ItemsRepeater, IEnumerable?>(
-                nameof(Items),
+                nameof(ItemsSource),
-                o => o.Items,
+                o => o.ItemsSource,
-                (o, v) => o.Items = v);
+                (o, v) => o.ItemsSource = v);
 
         /// <summary>
         /// Defines the <see cref="Layout"/> property.
@@ -65,7 +65,7 @@ namespace Avalonia.Controls
         private readonly ViewManager _viewManager;
         private readonly ViewportManager _viewportManager;
         private readonly TargetWeakEventSubscriber<ItemsRepeater, EventArgs> _layoutWeakSubscriber;
-        private IEnumerable? _items;
+        private IEnumerable? _itemsSource;
         private RepeaterLayoutContext? _layoutContext;
         private EventHandler<ChildIndexChangedEventArgs>? _childIndexChanged;
         private bool _isLayoutInProgress;
@@ -116,16 +116,16 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets or sets an object source used to generate the content of the ItemsRepeater.
         /// </summary>
-        public IEnumerable? Items
+        public IEnumerable? ItemsSource
         {
-            get => _items;
+            get => _itemsSource;
-            set => SetAndRaise(ItemsProperty, ref _items, value);
+            set => SetAndRaise(ItemsSourceProperty, ref _itemsSource, value);
         }
 
         /// <summary>
         /// Gets or sets the template used to display each item.
         /// </summary>
-        [InheritDataTypeFromItems(nameof(Items))]
+        [InheritDataTypeFromItems(nameof(ItemsSource))]
         public IDataTemplate? ItemTemplate
         {
             get => GetValue(ItemTemplateProperty);
@@ -415,7 +415,7 @@ namespace Avalonia.Controls
         /// <inheritdoc />
         protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
         {
-            if (change.Property == ItemsProperty)
+            if (change.Property == ItemsSourceProperty)
             {
                 var (oldEnumerable, newEnumerable) = change.GetOldAndNewValue<IEnumerable?>();
 

src/Avalonia.Controls/AutoCompleteBox/AutoCompleteBox.Properties.cs

@@ -143,12 +143,12 @@ namespace Avalonia.Controls
                 nameof(TextSelector));
 
         /// <summary>
-        /// Identifies the <see cref="Items" /> property.
+        /// Identifies the <see cref="ItemsSource" /> property.
         /// </summary>
-        /// <value>The identifier for the <see cref="Items" /> property.</value>
+        /// <value>The identifier for the <see cref="ItemsSource" /> property.</value>
-        public static readonly StyledProperty<IEnumerable?> ItemsProperty =
+        public static readonly StyledProperty<IEnumerable?> ItemsSourceProperty =
             AvaloniaProperty.Register<AutoCompleteBox, IEnumerable?>(
-                nameof(Items));
+                nameof(ItemsSource));
 
         /// <summary>
         /// Identifies the <see cref="AsyncPopulator" /> property.
@@ -311,10 +311,10 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets the text that is used to filter items in the
-        /// <see cref="Items" /> item collection.
+        /// <see cref="ItemsSource" /> item collection.
         /// </summary>
         /// <value>The text that is used to filter items in the
-        /// <see cref="Items" /> item collection.</value>
+        /// <see cref="ItemsSource" /> item collection.</value>
         /// <remarks>
         /// The SearchText value is typically the same as the
         /// Text property, but is set after the TextChanged event occurs
@@ -339,7 +339,7 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets or sets how the text in the text box is used to filter items
-        /// specified by the <see cref="Items" />
+        /// specified by the <see cref="ItemsSource" />
         /// property for display in the drop-down.
         /// </summary>
         /// <value>One of the <see cref="AutoCompleteFilterMode" />
@@ -366,11 +366,11 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets or sets the custom method that uses user-entered text to filter
-        /// the items specified by the <see cref="Items" />
+        /// the items specified by the <see cref="ItemsSource" />
         /// property for display in the drop-down.
         /// </summary>
         /// <value>The custom method that uses the user-entered text to filter
-        /// the items specified by the <see cref="Items" />
+        /// the items specified by the <see cref="ItemsSource" />
         /// property. The default is null.</value>
         /// <remarks>
         /// The filter mode is automatically set to Custom if you set the
@@ -384,11 +384,11 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets or sets the custom method that uses the user-entered text to
-        /// filter items specified by the <see cref="Items" />
+        /// filter items specified by the <see cref="ItemsSource" />
         /// property in a text-based way for display in the drop-down.
         /// </summary>
         /// <value>The custom method that uses the user-entered text to filter
-        /// items specified by the <see cref="Items" />
+        /// items specified by the <see cref="ItemsSource" />
         /// property in a text-based way for display in the drop-down.</value>
         /// <remarks>
         /// The search mode is automatically set to Custom if you set the
@@ -402,11 +402,11 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets or sets the custom method that combines the user-entered
-        /// text and one of the items specified by the <see cref="Items" />.
+        /// text and one of the items specified by the <see cref="ItemsSource" />.
         /// </summary>
         /// <value>
         /// The custom method that combines the user-entered
-        /// text and one of the items specified by the <see cref="Items" />.
+        /// text and one of the items specified by the <see cref="ItemsSource" />.
         /// </value>
         public AutoCompleteSelector<object>? ItemSelector
         {
@@ -417,11 +417,11 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets or sets the custom method that combines the user-entered
         /// text and one of the items specified by the
-        /// <see cref="Items" /> in a text-based way.
+        /// <see cref="ItemsSource" /> in a text-based way.
         /// </summary>
         /// <value>
         /// The custom method that combines the user-entered
-        /// text and one of the items specified by the <see cref="Items" />
+        /// text and one of the items specified by the <see cref="ItemsSource" />
         /// in a text-based way.
         /// </value>
         public AutoCompleteSelector<string?>? TextSelector
@@ -442,10 +442,10 @@ namespace Avalonia.Controls
         /// </summary>
         /// <value>The collection that is used to generate the items of the
         /// drop-down portion of the <see cref="AutoCompleteBox" /> control.</value>
-        public IEnumerable? Items
+        public IEnumerable? ItemsSource
         {
-            get => GetValue(ItemsProperty);
+            get => GetValue(ItemsSourceProperty);
-            set => SetValue(ItemsProperty, value);
+            set => SetValue(ItemsSourceProperty, value);
         }
     }
 }

src/Avalonia.Controls/AutoCompleteBox/AutoCompleteBox.cs

@@ -419,9 +419,9 @@ namespace Avalonia.Controls
         /// ItemsSourceProperty property changed handler.
         /// </summary>
         /// <param name="e">Event arguments.</param>
-        private void OnItemsPropertyChanged(AvaloniaPropertyChangedEventArgs e)
+        private void OnItemsSourcePropertyChanged(AvaloniaPropertyChangedEventArgs e)
         {
-            OnItemsChanged((IEnumerable?)e.NewValue);
+            OnItemsSourceChanged((IEnumerable?)e.NewValue);
         }
 
         private void OnItemTemplatePropertyChanged(AvaloniaPropertyChangedEventArgs e)
@@ -461,7 +461,7 @@ namespace Avalonia.Controls
             SearchTextProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnSearchTextPropertyChanged(e));
             FilterModeProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnFilterModePropertyChanged(e));
             ItemFilterProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnItemFilterPropertyChanged(e));
-            ItemsProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnItemsPropertyChanged(e));
+            ItemsSourceProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnItemsSourcePropertyChanged(e));
             ItemTemplateProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnItemTemplatePropertyChanged(e));
             IsEnabledProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnControlIsEnabledChanged(e));
         }
@@ -559,7 +559,7 @@ namespace Avalonia.Controls
                     _adapter.Commit -= OnAdapterSelectionComplete;
                     _adapter.Cancel -= OnAdapterSelectionCanceled;
                     _adapter.Cancel -= OnAdapterSelectionComplete;
-                    _adapter.Items = null;
+                    _adapter.ItemsSource = null;
                 }
 
                 _adapter = value;
@@ -570,7 +570,7 @@ namespace Avalonia.Controls
                     _adapter.Commit += OnAdapterSelectionComplete;
                     _adapter.Cancel += OnAdapterSelectionCanceled;
                     _adapter.Cancel += OnAdapterSelectionComplete;
-                    _adapter.Items = _view;
+                    _adapter.ItemsSource = _view;
                 }
             }
         }
@@ -1128,7 +1128,7 @@ namespace Avalonia.Controls
                 {
                     if (!cancellationToken.IsCancellationRequested)
                     {
-                        SetCurrentValue(ItemsProperty, resultList);
+                        SetCurrentValue(ItemsSourceProperty, resultList);
                         PopulateComplete();
                     }
                 });
@@ -1475,7 +1475,7 @@ namespace Avalonia.Controls
         /// adapter's ItemsSource to the view if appropriate.
         /// </summary>
         /// <param name="newValue">The new enumerable reference.</param>
-        private void OnItemsChanged(IEnumerable? newValue)
+        private void OnItemsSourceChanged(IEnumerable? newValue)
         {
             // Remove handler for oldValue.CollectionChanged (if present)
             _collectionChangeSubscription?.Dispose();
@@ -1492,9 +1492,9 @@ namespace Avalonia.Controls
 
             // Clear and set the view on the selection adapter
             ClearView();
-            if (SelectionAdapter != null && SelectionAdapter.Items != _view)
+            if (SelectionAdapter != null && SelectionAdapter.ItemsSource != _view)
             {
-                SelectionAdapter.Items = _view;
+                SelectionAdapter.ItemsSource = _view;
             }
             if (IsDropDownOpen)
             {
@@ -1545,9 +1545,9 @@ namespace Avalonia.Controls
             {
                 // Significant changes to the underlying data.
                 ClearView();
-                if (Items != null)
+                if (ItemsSource != null)
                 {
-                    _items = new List<object>(Items.Cast<object>());
+                    _items = new List<object>(ItemsSource.Cast<object>());
                 }
             }
 
@@ -1582,9 +1582,9 @@ namespace Avalonia.Controls
             PopulatedEventArgs populated = new PopulatedEventArgs(new ReadOnlyCollection<object>(_view!));
             OnPopulated(populated);
 
-            if (SelectionAdapter != null && SelectionAdapter.Items != _view)
+            if (SelectionAdapter != null && SelectionAdapter.ItemsSource != _view)
             {
-                SelectionAdapter.Items = _view;
+                SelectionAdapter.ItemsSource = _view;
             }
 
             bool isDropDownOpen = _userCalledPopulate && (_view!.Count > 0);

src/Avalonia.Controls/CalendarDatePicker/CalendarDatePicker.cs

@@ -875,10 +875,11 @@ namespace Avalonia.Controls
         {
             if (_textBox != null)
             {
+                SetCurrentValue(TextProperty, String.Empty);
+                
                 if (string.IsNullOrEmpty(Watermark) && !UseFloatingWatermark)
                 {
                     DateTimeFormatInfo dtfi = DateTimeHelper.GetCurrentDateFormat();
-                    SetCurrentValue(TextProperty, string.Empty);
                     _defaultText = string.Empty;
                     var watermarkFormat = "<{0}>";
                     string watermarkText;

src/Avalonia.Controls/Flyouts/MenuFlyout.cs

@@ -1,6 +1,5 @@
 using System.Collections;
 using System.ComponentModel;
-using Avalonia.Collections;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
 using Avalonia.Metadata;
@@ -12,17 +11,15 @@ namespace Avalonia.Controls
     {
         public MenuFlyout()
         {
-            _items = new AvaloniaList<object>();
+            Items = new ItemCollection();
         }
 
         /// <summary>
-        /// Defines the <see cref="Items"/> property
+        /// Defines the <see cref="ItemsSource"/> property
         /// </summary>
-        public static readonly DirectProperty<MenuFlyout, IEnumerable?> ItemsProperty =
+        public static readonly StyledProperty<IEnumerable?> ItemsSourceProperty =
-            AvaloniaProperty.RegisterDirect<MenuFlyout, IEnumerable?>(
+            AvaloniaProperty.Register<MenuFlyout, IEnumerable?>(
-                nameof(Items),
+                nameof(ItemsSource));
-                x => x.Items,
-                (x, v) => x.Items = v);
 
         /// <summary>
         /// Defines the <see cref="ItemTemplate"/> property
@@ -45,14 +42,16 @@ namespace Avalonia.Controls
         
         public Classes FlyoutPresenterClasses => _classes ??= new Classes();
 
+        [Content]
+        public ItemCollection Items { get; }
+
         /// <summary>
         /// Gets or sets the items of the MenuFlyout
         /// </summary>
-        [Content]
+        public IEnumerable? ItemsSource
-        public IEnumerable? Items
         {
-            get => _items;
+            get => GetValue(ItemsSourceProperty);
-            set => SetAndRaise(ItemsProperty, ref _items, value);
+            set => SetValue(ItemsSourceProperty, value);
         }
 
         /// <summary>
@@ -83,14 +82,13 @@ namespace Avalonia.Controls
         }
         
         private Classes? _classes;
-        private IEnumerable? _items;
         private IDataTemplate? _itemTemplate;
 
         protected override Control CreatePresenter()
         {
             return new MenuFlyoutPresenter
             {
-                [!ItemsControl.ItemsSourceProperty] = this[!ItemsProperty],
+                ItemsSource = Items,
                 [!ItemsControl.ItemTemplateProperty] = this[!ItemTemplateProperty],
                 [!ItemsControl.ItemContainerThemeProperty] = this[!ItemContainerThemeProperty],
             };
@@ -113,5 +111,13 @@ namespace Avalonia.Controls
 
             base.OnOpening(args);
         }
+
+        protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+        {
+            base.OnPropertyChanged(change);
+
+            if (change.Property == ItemsSourceProperty)
+                Items.SetItemsSource(change.GetNewValue<IEnumerable?>());
+        }
     }
 }

src/Avalonia.Controls/ItemsControl.cs

@@ -378,48 +378,48 @@ namespace Avalonia.Controls
 
             if (container is HeaderedContentControl hcc)
             {
-                hcc.Content = item;
+                SetIfUnset(hcc, HeaderedContentControl.ContentProperty, item);
 
                 if (item is IHeadered headered)
-                    hcc.Header = headered.Header;
+                    SetIfUnset(hcc, HeaderedContentControl.HeaderProperty, headered.Header);
                 else if (item is not Visual)
-                    hcc.Header = item;
+                    SetIfUnset(hcc, HeaderedContentControl.HeaderProperty, item);
 
                 if (itemTemplate is not null)
-                    hcc.HeaderTemplate = itemTemplate;
+                    SetIfUnset(hcc, HeaderedContentControl.HeaderTemplateProperty, itemTemplate);
             }
             else if (container is ContentControl cc)
             {
-                cc.Content = item;
+                SetIfUnset(cc, ContentControl.ContentProperty, item);
                 if (itemTemplate is not null)
-                    cc.ContentTemplate = itemTemplate;
+                    SetIfUnset(cc, ContentControl.ContentTemplateProperty, itemTemplate);
             }
             else if (container is ContentPresenter p)
             {
-                p.Content = item;
+                SetIfUnset(p, ContentPresenter.ContentProperty, item);
                 if (itemTemplate is not null)
-                    p.ContentTemplate = itemTemplate;
+                    SetIfUnset(p, ContentPresenter.ContentTemplateProperty, itemTemplate);
             }
             else if (container is ItemsControl ic)
             {
                 if (itemTemplate is not null)
-                    ic.ItemTemplate = itemTemplate;
+                    SetIfUnset(ic, ItemTemplateProperty, itemTemplate);
-                if (ItemContainerTheme is { } ict && !ict.IsSet(ItemContainerThemeProperty))
+                if (ItemContainerTheme is { } ict)
-                    ic.ItemContainerTheme = ict;
+                    SetIfUnset(ic, ItemContainerThemeProperty, ict);
             }
 
             // These conditions are separate because HeaderedItemsControl and
             // HeaderedSelectingItemsControl also need to run the ItemsControl preparation.
             if (container is HeaderedItemsControl hic)
             {
-                hic.Header = item;
+                SetIfUnset(hic, HeaderedItemsControl.HeaderProperty, item);
-                hic.HeaderTemplate = itemTemplate;
+                SetIfUnset(hic, HeaderedItemsControl.HeaderTemplateProperty, itemTemplate);
                 hic.PrepareItemContainer(this);
             }
             else if (container is HeaderedSelectingItemsControl hsic)
             {
-                hsic.Header = item;
+                SetIfUnset(hsic, HeaderedSelectingItemsControl.HeaderProperty, item);
-                hsic.HeaderTemplate = itemTemplate;
+                SetIfUnset(hsic, HeaderedSelectingItemsControl.HeaderTemplateProperty, itemTemplate);
                 hsic.PrepareItemContainer(this);
             }
         }
@@ -458,30 +458,35 @@ namespace Avalonia.Controls
         {
             if (container is HeaderedContentControl hcc)
             {
-                if (hcc.Content is Control)
+                hcc.ClearValue(HeaderedContentControl.ContentProperty);
-                    hcc.Content = null;
+                hcc.ClearValue(HeaderedContentControl.HeaderProperty);
-                if (hcc.Header is Control)
+                hcc.ClearValue(HeaderedContentControl.HeaderTemplateProperty);
-                    hcc.Header = null;
             }
             else if (container is ContentControl cc)
             {
-                if (cc.Content is Control)
+                cc.ClearValue(ContentControl.ContentProperty);
-                    cc.Content = null;
+                cc.ClearValue(ContentControl.ContentTemplateProperty);
             }
             else if (container is ContentPresenter p)
             {
-                if (p.Content is Control)
+                p.ClearValue(ContentPresenter.ContentProperty);
-                    p.Content = null;
+                p.ClearValue(ContentPresenter.ContentTemplateProperty);
             }
-            else if (container is HeaderedItemsControl hic)
+            else if (container is ItemsControl ic)
+            {
+                ic.ClearValue(ItemTemplateProperty);
+                ic.ClearValue(ItemContainerThemeProperty);
+            }
+            
+            if (container is HeaderedItemsControl hic)
             {
-                if (hic.Header is Control)
+                hic.ClearValue(HeaderedItemsControl.HeaderProperty);
-                    hic.Header = null;
+                hic.ClearValue(HeaderedItemsControl.HeaderTemplateProperty);
             }
             else if (container is HeaderedSelectingItemsControl hsic)
             {
-                if (hsic.Header is Control)
+                hsic.ClearValue(HeaderedSelectingItemsControl.HeaderProperty);
-                    hsic.Header = null;
+                hsic.ClearValue(HeaderedSelectingItemsControl.HeaderTemplateProperty);
             }
 
             // Feels like we should be clearing the HeaderedItemsControl.Items binding here, but looking at
@@ -707,6 +712,12 @@ namespace Avalonia.Controls
                 LogicalChildren.AddRange(toAdd);
         }
 
+        private void SetIfUnset<T>(AvaloniaObject target, StyledProperty<T> property, T value)
+        {
+            if (!target.IsSet(property))
+                target.SetCurrentValue(property, value);
+        }
+
         private void RemoveControlItemsFromLogicalChildren(IEnumerable? items)
         {
             if (items is null)

src/Avalonia.Controls/ItemsSourceView.cs

@@ -262,7 +262,7 @@ namespace Avalonia.Controls
 
             _source = source switch
             {
-                ItemsSourceView => throw new ArgumentException("Cannot wrap an existing ItemsSourceView.", nameof(source)),
+                ItemsSourceView isv => isv.Source,
                 IList list => list,
                 INotifyCollectionChanged => throw new ArgumentException(
                     "Collection implements INotifyCollectionChanged but not IList.",

src/Avalonia.Controls/RadioButton.cs

@@ -86,7 +86,7 @@ namespace Avalonia.Controls
                                 continue;
                             }
                             if (current != radioButton && current.IsChecked.GetValueOrDefault())
-                                current.IsChecked = false;
+                                current.SetCurrentValue(IsCheckedProperty, false);
                             i++;
                         }
                         if (group.Count == 0)
@@ -193,7 +193,7 @@ namespace Avalonia.Controls
                     foreach (var sibling in siblings)
                     {
                         if (sibling.IsChecked.GetValueOrDefault())
-                            sibling.IsChecked = false;
+                            sibling.SetCurrentValue(IsCheckedProperty, false);
                     }
                 }
             }

src/Avalonia.Controls/Templates/FuncControlTemplate.cs

@@ -18,10 +18,10 @@ namespace Avalonia.Controls.Templates
         {
         }
 
-        public new ControlTemplateResult Build(TemplatedControl param)
+        public new TemplateResult<Control> Build(TemplatedControl param)
         {
             var (control, scope) = BuildWithNameScope(param);
-            return new ControlTemplateResult(control, scope);
+            return new(control, scope);
         }
     }
 }

src/Avalonia.Controls/Templates/IControlTemplate.cs

@@ -5,23 +5,7 @@ namespace Avalonia.Controls.Templates
     /// <summary>
     /// Interface representing a template used to build a <see cref="TemplatedControl"/>.
     /// </summary>
-    public interface IControlTemplate : ITemplate<TemplatedControl, ControlTemplateResult?>
+    public interface IControlTemplate : ITemplate<TemplatedControl, TemplateResult<Control>?>
     {
     }
-
-    public class ControlTemplateResult : TemplateResult<Control>
-    {
-        public Control Control { get; }
-
-        public ControlTemplateResult(Control control, INameScope nameScope) : base(control, nameScope)
-        {
-            Control = control;
-        }
-
-        public new void Deconstruct(out Control control, out INameScope scope)
-        {
-            control = Control;
-            scope = NameScope;
-        }
-    }
 }

src/Avalonia.Controls/Utils/ISelectionAdapter.cs

@@ -36,7 +36,7 @@ namespace Avalonia.Controls.Utils
         /// </summary>
         /// <value>The collection that is used to generate content for the
         /// selection adapter.</value>
-        IEnumerable? Items { get; set; }
+        IEnumerable? ItemsSource { get; set; }
 
         /// <summary>
         /// Occurs when a selected item is not cancelled and is committed as the

src/Avalonia.Controls/Utils/SelectingItemsControlSelectionAdapter.cs

@@ -140,7 +140,7 @@ namespace Avalonia.Controls.Utils
         /// </summary>
         /// <value>The collection used to generate content for the selection
         /// adapter.</value>
-        public IEnumerable? Items
+        public IEnumerable? ItemsSource
         {
             get
             {

src/Avalonia.Diagnostics/Diagnostics/Views/ControlDetailsView.xaml

@@ -51,7 +51,7 @@
       
       <DataGrid 
                 x:Name="DataGrid"
-                Items="{Binding PropertiesView}"
+                ItemsSource="{Binding PropertiesView}"
                 Grid.Row="2"
                 BorderThickness="0"
                 RowBackground="Transparent"

src/Avalonia.Themes.Fluent/Controls/TextBox.xaml

@@ -1,4 +1,4 @@
-<ResourceDictionary xmlns="https://github.com/avaloniaui"
+<ResourceDictionary xmlns="https://github.com/avaloniaui"
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Design.PreviewWith>
     <Border Padding="20">
@@ -26,12 +26,6 @@
     <MenuItem x:Name="TextBoxContextFlyoutPasteItem" Header="Paste" Command="{Binding $parent[TextBox].Paste}" IsEnabled="{Binding $parent[TextBox].CanPaste}" InputGesture="{x:Static TextBox.PasteGesture}"/>
   </MenuFlyout>
 
-  <ContextMenu x:Key="DefaultTextBoxContextMenu" x:Name="TextBoxContextMenu">
-    <MenuItem x:Name="TextBoxContextMenuCutItem" Header="Cut" Command="{Binding $parent[TextBox].Cut}" IsEnabled="{Binding $parent[TextBox].CanCut}" InputGesture="{x:Static TextBox.CutGesture}" />
-    <MenuItem x:Name="TextBoxContextMenuCopyItem" Header="Copy" Command="{Binding $parent[TextBox].Copy}" IsEnabled="{Binding $parent[TextBox].CanCopy}" InputGesture="{x:Static TextBox.CopyGesture}"/>
-    <MenuItem x:Name="TextBoxContextMenuPasteItem" Header="Paste" Command="{Binding $parent[TextBox].Paste}" IsEnabled="{Binding $parent[TextBox].CanPaste}" InputGesture="{x:Static TextBox.PasteGesture}"/>
-  </ContextMenu>
-
   <ControlTheme x:Key="FluentTextBoxButton" TargetType="Button">
     <Setter Property="Background" Value="{DynamicResource TextControlButtonBackground}" />
     <Setter Property="BorderBrush" Value="{DynamicResource TextControlButtonBorderBrush}" />

src/Avalonia.Themes.Simple/Controls/TextBox.xaml

@@ -13,15 +13,6 @@
               IsEnabled="{Binding $parent[TextBox].CanPaste}" InputGesture="{x:Static TextBox.PasteGesture}" />
   </MenuFlyout>
 
-  <ContextMenu x:Key="SimpleTextBoxContextMenu" x:Name="TextBoxContextMenu">
-    <MenuItem x:Name="TextBoxContextMenuCutItem" Header="Cut" Command="{Binding $parent[TextBox].Cut}"
-              IsEnabled="{Binding $parent[TextBox].CanCut}" InputGesture="{x:Static TextBox.CutGesture}" />
-    <MenuItem x:Name="TextBoxContextMenuCopyItem" Header="Copy" Command="{Binding $parent[TextBox].Copy}"
-              IsEnabled="{Binding $parent[TextBox].CanCopy}" InputGesture="{x:Static TextBox.CopyGesture}" />
-    <MenuItem x:Name="TextBoxContextMenuPasteItem" Header="Paste" Command="{Binding $parent[TextBox].Paste}"
-              IsEnabled="{Binding $parent[TextBox].CanPaste}" InputGesture="{x:Static TextBox.PasteGesture}" />
-  </ContextMenu>
-
   <ControlTheme x:Key="SimpleTextBoxClearButtonTheme"
                 BasedOn="{StaticResource {x:Type Button}}"
                 TargetType="Button">

src/Markup/Avalonia.Markup.Xaml/Templates/ControlTemplate.cs

@@ -1,4 +1,5 @@
 using System;
+using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
 using Avalonia.Metadata;
@@ -13,6 +14,6 @@ namespace Avalonia.Markup.Xaml.Templates
 
         public Type? TargetType { get; set; }
 
-        public ControlTemplateResult? Build(TemplatedControl control) => TemplateContent.Load(Content);
+        public TemplateResult<Control>? Build(TemplatedControl control) => TemplateContent.Load(Content);
     }
 }

src/Markup/Avalonia.Markup.Xaml/Templates/DataTemplate.cs

@@ -30,7 +30,7 @@ namespace Avalonia.Markup.Xaml.Templates
 
         public Control? Build(object? data, Control? existing)
         {
-            return existing ?? TemplateContent.Load(Content)?.Control;
+            return existing ?? TemplateContent.Load(Content)?.Result;
         }
     }
 }

src/Markup/Avalonia.Markup.Xaml/Templates/ItemsPanelTemplate.cs

@@ -10,7 +10,7 @@ namespace Avalonia.Markup.Xaml.Templates
         [TemplateContent]
         public object? Content { get; set; }
 
-        public Panel? Build() => (Panel?)TemplateContent.Load(Content)?.Control;
+        public Panel? Build() => (Panel?)TemplateContent.Load(Content)?.Result;
 
         object? ITemplate.Build() => Build();
     }

src/Markup/Avalonia.Markup.Xaml/Templates/Template.cs

@@ -10,7 +10,7 @@ namespace Avalonia.Markup.Xaml.Templates
         [TemplateContent]
         public object? Content { get; set; }
 
-        public Control? Build() => TemplateContent.Load(Content)?.Control;
+        public Control? Build() => TemplateContent.Load(Content)?.Result;
 
         object? ITemplate.Build() => Build();
     }

src/Markup/Avalonia.Markup.Xaml/Templates/TemplateContent.cs

@@ -1,15 +1,16 @@
 using System;
+using Avalonia.Controls;
 using Avalonia.Controls.Templates;
 
 namespace Avalonia.Markup.Xaml.Templates
 {
     public static class TemplateContent
     {
-        public static ControlTemplateResult? Load(object? templateContent)
+        public static TemplateResult<Control>? Load(object? templateContent)
         {
             if (templateContent is Func<IServiceProvider?, object?> direct)
             {
-                return (ControlTemplateResult?)direct(null);
+                return (TemplateResult<Control>?)direct(null);
             }
 
             if (templateContent is null)

src/Markup/Avalonia.Markup.Xaml/Templates/TreeDataTemplate.cs

@@ -54,7 +54,7 @@ namespace Avalonia.Markup.Xaml.Templates
 
         public Control? Build(object? data)
         {
-            var visualTreeForItem = TemplateContent.Load(Content)?.Control;
+            var visualTreeForItem = TemplateContent.Load(Content)?.Result;
             if (visualTreeForItem != null)
             {
                 visualTreeForItem.DataContext = data;

src/Markup/Avalonia.Markup.Xaml/XamlIl/Runtime/XamlIlRuntimeHelpers.cs

@@ -35,7 +35,7 @@ namespace Avalonia.Markup.Xaml.XamlIl.Runtime
                 scope.Complete();
 
                 if(typeof(T) == typeof(Control))
-                    return new ControlTemplateResult((Control)obj, scope);
+                    return new TemplateResult<Control>((Control)obj, scope);
 
                 return new TemplateResult<T>((T)obj, scope);
             };

tests/Avalonia.Controls.ItemsRepeater.UnitTests/ItemsRepeaterTests.cs

@@ -9,16 +9,16 @@ namespace Avalonia.Controls.UnitTests
         public void Can_Reassign_Items()
         {
             var target = new ItemsRepeater();
-            target.Items = new ObservableCollection<string>();
+            target.ItemsSource = new ObservableCollection<string>();
-            target.Items = new ObservableCollection<string>();
+            target.ItemsSource = new ObservableCollection<string>();
         }
 
         [Fact]
         public void Can_Reassign_Items_To_Null()
         {
             var target = new ItemsRepeater();
-            target.Items = new ObservableCollection<string>();
+            target.ItemsSource = new ObservableCollection<string>();
-            target.Items = null;
+            target.ItemsSource = null;
         }
     }
 }

tests/Avalonia.Controls.UnitTests/AutoCompleteBoxTests.cs

@@ -89,7 +89,7 @@ namespace Avalonia.Controls.UnitTests
                 bool closeEvent = false;
                 control.DropDownOpened += (s, e) => openEvent = true;
                 control.DropDownClosed += (s, e) => closeEvent = true;
-                control.Items = CreateSimpleStringArray();
+                control.ItemsSource = CreateSimpleStringArray();
 
                 textbox.Text = "a";
                 Dispatcher.UIThread.RunJobs();
@@ -258,7 +258,7 @@ namespace Avalonia.Controls.UnitTests
                 control.FilterMode = AutoCompleteFilterMode.None;
                 control.Populating += (s, e) =>
                 {
-                    control.Items = new string[] { custom };
+                    control.ItemsSource = new string[] { custom };
                     Assert.Equal(search, e.Parameter);
                 };
                 control.Populated += (s, e) =>
@@ -380,7 +380,7 @@ namespace Avalonia.Controls.UnitTests
         {
             RunTest((control, textbox) =>
             {
-                object selectedItem = control.Items.Cast<object>().First();
+                object selectedItem = control.ItemsSource.Cast<object>().First();
                 string input = "42";
 
                 control.TextSelector = (text, item) => text + item;
@@ -397,7 +397,7 @@ namespace Avalonia.Controls.UnitTests
         {
             RunTest((control, textbox) =>
             {
-                object selectedItem = control.Items.Cast<object>().First();
+                object selectedItem = control.ItemsSource.Cast<object>().First();
                 string input = "42";
 
                 control.ItemSelector = (text, item) => text + item;
@@ -1053,7 +1053,7 @@ namespace Avalonia.Controls.UnitTests
             using (UnitTestApplication.Start(Services))
             {
                 AutoCompleteBox control = CreateControl();
-                control.Items = CreateSimpleStringArray();
+                control.ItemsSource = CreateSimpleStringArray();
                 TextBox textBox = GetTextBox(control);
                 var window = new Window {Content = control};
                 window.ApplyStyling();

tests/Avalonia.Controls.UnitTests/ListBoxTests.cs

@@ -554,6 +554,36 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(new[] { "Bar" }, target.Selection.SelectedItems);
         }
 
+        [Fact]
+        public void Content_Can_Be_Bound_In_ItemContainerTheme()
+        {
+            using (UnitTestApplication.Start(TestServices.MockPlatformRenderInterface))
+            {
+                var items = new[] { new ItemViewModel("Foo"), new ItemViewModel("Bar") };
+                var theme = new ControlTheme(typeof(ListBoxItem))
+                {
+                    Setters =
+                    {
+                        new Setter(ListBoxItem.ContentProperty, new Binding("Caption")),
+                    }
+                };
+
+                var target = new ListBox
+                {
+                    Template = ListBoxTemplate(),
+                    ItemsSource = items,
+                    ItemContainerTheme = theme,
+                };
+
+                Prepare(target);
+
+                var containers = target.GetRealizedContainers().Cast<ListBoxItem>().ToList();
+                Assert.Equal(2, containers.Count);
+                Assert.Equal("Foo", containers[0].Content);
+                Assert.Equal("Bar", containers[1].Content);
+            }
+        }
+
         private static FuncControlTemplate ListBoxTemplate()
         {
             return new FuncControlTemplate<ListBox>((parent, scope) =>
@@ -918,6 +948,8 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(1, raised);
         }
 
+        private record ItemViewModel(string Caption);
+
         private class ResettingCollection : List<string>, INotifyCollectionChanged
         {
             public ResettingCollection(int itemCount)

tests/Avalonia.Controls.UnitTests/MaskedTextBoxTests.cs

@@ -72,7 +72,7 @@ namespace Avalonia.Controls.UnitTests
                     Text = "1234",
                     ContextFlyout = new MenuFlyout
                     {
-                        Items = new List<MenuItem>
+                        Items =
                         {
                             new MenuItem { Header = "Item 1" },
                             new MenuItem {Header = "Item 2" },

tests/Avalonia.Controls.UnitTests/MenuItemTests.cs

@@ -1,16 +1,16 @@
 using System;
+using System.Collections;
 using System.Collections.Generic;
-using System.Text;
+using System.Linq;
 using System.Windows.Input;
-using Avalonia.Collections;
 using Avalonia.Controls.Presenters;
-using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
+using Avalonia.Controls.Utils;
 using Avalonia.Data;
 using Avalonia.Input;
 using Avalonia.Platform;
+using Avalonia.Styling;
 using Avalonia.UnitTests;
-using Avalonia.VisualTree;
 using Moq;
 using Xunit;
 
@@ -36,7 +36,6 @@ namespace Avalonia.Controls.UnitTests
             Assert.False(target.Focusable);
         }
 
-
         [Fact]
         public void MenuItem_Is_Disabled_When_Command_Is_Enabled_But_IsEnabled_Is_False()
         {
@@ -232,7 +231,7 @@ namespace Avalonia.Controls.UnitTests
                     return true;
                 });
                 var target = new MenuItem();
-                var flyout = new MenuFlyout { Items = new AvaloniaList<MenuItem> { target } };
+                var flyout = new MenuFlyout { Items = { target } };
                 var button = new Button { Flyout = flyout };
                 var window = new Window { Content = button };
                 window.ApplyStyling();
@@ -393,6 +392,87 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Fact]
+        public void Header_And_ItemsSource_Can_Be_Bound_In_Style()
+        {
+            using var app = Application();
+            var items = new[]
+            {
+                new MenuViewModel("Foo")
+                {
+                    Children = new[]
+                    {
+                        new MenuViewModel("FooChild"),
+                    },
+                },
+                new MenuViewModel("Bar"),
+            };
+
+            var target = new Menu
+            {
+                ItemsSource = items,
+                Styles =
+                {
+                    new Style(x => x.OfType<MenuItem>())
+                    {
+                        Setters =
+                        {
+                            new Setter(MenuItem.HeaderProperty, new Binding("Header")),
+                            new Setter(MenuItem.ItemsSourceProperty, new Binding("Children")),
+                        }
+                    }
+                }
+            };
+
+            var root = new TestRoot(true, target);
+            root.LayoutManager.ExecuteInitialLayoutPass();
+
+            var children = target.GetRealizedContainers().Cast<MenuItem>().ToList();
+            Assert.Equal(2, children.Count);
+            Assert.Equal("Foo", children[0].Header);
+            Assert.Equal("Bar", children[1].Header);
+            Assert.Same(items[0].Children, children[0].ItemsSource);
+        }
+
+        [Fact]
+        public void Header_And_ItemsSource_Can_Be_Bound_In_ItemContainerTheme()
+        {
+            using var app = Application();
+            var items = new[]
+            {
+                new MenuViewModel("Foo")
+                {
+                    Children = new[]
+                    {
+                        new MenuViewModel("FooChild"),
+                    },
+                },
+                new MenuViewModel("Bar"),
+            };
+
+            var target = new Menu
+            {
+                ItemsSource = items,
+                ItemContainerTheme = new ControlTheme(typeof(MenuItem))
+                {
+                    Setters =
+                    {
+                        new Setter(MenuItem.HeaderProperty, new Binding("Header")),
+                        new Setter(MenuItem.ItemsSourceProperty, new Binding("Children")),
+                    }
+                }
+            };
+
+            var root = new TestRoot(true, target);
+            root.LayoutManager.ExecuteInitialLayoutPass();
+
+            var children = target.GetRealizedContainers().Cast<MenuItem>().ToList();
+            Assert.Equal(2, children.Count);
+            Assert.Equal("Foo", children[0].Header);
+            Assert.Equal("Bar", children[1].Header);
+            Assert.Same(items[0].Children, children[0].ItemsSource);
+        }
+
         private IDisposable Application()
         {
             var screen = new PixelRect(new PixelPoint(), new PixelSize(100, 100));
@@ -447,6 +527,9 @@ namespace Avalonia.Controls.UnitTests
             public void RaiseCanExecuteChanged() => _canExecuteChanged?.Invoke(this, EventArgs.Empty);
         }
 
-        private record MenuViewModel(string Header);
+        private record MenuViewModel(string Header)
+        {
+            public IList<MenuViewModel> Children { get; set;}
+        }
     }
 }

tests/Avalonia.Controls.UnitTests/TextBoxTests.cs

@@ -93,7 +93,7 @@ namespace Avalonia.Controls.UnitTests
                     Text = "1234",
                     ContextFlyout = new MenuFlyout
                     {
-                        Items = new List<MenuItem>
+                        Items =
                         {
                             new MenuItem { Header = "Item 1" },
                             new MenuItem {Header = "Item 2" },

tests/Avalonia.IntegrationTests.Appium/NativeMenuTests.cs

@@ -18,7 +18,7 @@ namespace Avalonia.IntegrationTests.Appium
         }
 
         [PlatformFact(TestPlatforms.MacOS)]
-        public void View_Menu_Select_Button_Tab()
+        public void MacOS_View_Menu_Select_Button_Tab()
         {
             var tabs = _session.FindElementByAccessibilityId("MainTabs");
             var buttonTab = tabs.FindElementByName("Button");
@@ -33,5 +33,21 @@ namespace Avalonia.IntegrationTests.Appium
 
             Assert.True(buttonTab.Selected);
         }
+
+        [PlatformFact(TestPlatforms.Windows)]
+        public void Win32_View_Menu_Select_Button_Tab()
+        {
+            var tabs = _session.FindElementByAccessibilityId("MainTabs");
+            var buttonTab = tabs.FindElementByName("Button");
+            var viewMenu = _session.FindElementByXPath("//MenuItem[@Name='View']");
+
+            Assert.False(buttonTab.Selected);
+
+            viewMenu.Click();
+            var buttonMenu = viewMenu.FindElementByName("Button");
+            buttonMenu.Click();
+
+            Assert.True(buttonTab.Selected);
+        }
     }
 }

tests/Avalonia.LeakTests/ControlTests.cs

@@ -51,7 +51,7 @@ namespace Avalonia.LeakTests
                     {
                         Content = new DataGrid
                         {
-                            Items = _observableCollection
+                            ItemsSource = _observableCollection
                         }
                     };
 

tests/Avalonia.Markup.Xaml.UnitTests/MarkupExtensions/CompiledBindingExtensionTests.cs

@@ -1978,7 +1978,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.MarkupExtensions
 
         public bool Match(object data) => FancyDataType?.IsInstanceOfType(data) ?? true;
 
-        public Control Build(object data) => TemplateContent.Load(Content)?.Control;
+        public Control Build(object data) => TemplateContent.Load(Content)?.Result;
     }
     
     public class CustomDataTemplateInherit : CustomDataTemplate { }

tests/Avalonia.Markup.Xaml.UnitTests/Xaml/BasicTests.cs

@@ -605,7 +605,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
 
             var control = new ContentControl();
 
-            var result = (ContentPresenter)template.Build(control).Control;
+            var result = (ContentPresenter)template.Build(control).Result;
 
             Assert.NotNull(result);
         }

tests/Avalonia.Markup.Xaml.UnitTests/Xaml/ControlTemplateTests.cs

@@ -258,7 +258,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
 ";
             var template = AvaloniaRuntimeXamlLoader.Parse<ControlTemplate>(xaml);
 
-            var parent = (ContentControl)template.Build(new ContentControl()).Control;
+            var parent = (ContentControl)template.Build(new ContentControl()).Result;
 
             Assert.Equal("parent", parent.Name);
 
@@ -283,7 +283,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
 
             Assert.Equal(typeof(ContentControl), template.TargetType);
 
-            Assert.IsType(typeof(ContentPresenter), template.Build(new ContentControl()).Control);
+            Assert.IsType(typeof(ContentPresenter), template.Build(new ContentControl()).Result);
         }
 
         [Fact]
@@ -299,7 +299,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
 ";
             var template = AvaloniaRuntimeXamlLoader.Parse<ControlTemplate>(xaml);
 
-            var panel = (Panel)template.Build(new ContentControl()).Control;
+            var panel = (Panel)template.Build(new ContentControl()).Result;
 
             Assert.Equal(2, panel.Children.Count);
 

tests/Avalonia.Markup.Xaml.UnitTests/Xaml/StyleTests.cs

@@ -424,7 +424,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
                 };
 
                 var list = window.FindControl<ItemsRepeater>("list");
-                list.Items = collection;
+                list.ItemsSource = collection;
 
                 window.Show();