Merge branch 'master' into style-inspector

native/Avalonia.Native/src/OSX/common.h

@@ -28,6 +28,8 @@ extern IAvnNativeControlHost* CreateNativeControlHost(NSView* parent);
 extern void SetAppMenu (NSString* appName, IAvnMenu* appMenu);
 extern IAvnMenu* GetAppMenu ();
 extern NSMenuItem* GetAppMenuItem ();
+extern void SetAutoGenerateDefaultAppMenuItems (bool enabled);
+extern bool GetAutoGenerateDefaultAppMenuItems ();
 
 extern void InitializeAvnApp();
 extern NSApplicationActivationPolicy AvnDesiredActivationPolicy;

native/Avalonia.Native/src/OSX/main.mm

@@ -2,6 +2,7 @@
 #define COM_GUIDS_MATERIALIZE
 #include "common.h"
 
+static bool s_generateDefaultAppMenuItems = true;
 static NSString* s_appTitle = @"Avalonia";
 
 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
@@ -122,6 +123,12 @@ public:
             ? NSApplicationActivationPolicyRegular : NSApplicationActivationPolicyAccessory;
         return S_OK;
     }
+    
+    virtual HRESULT SetDisableDefaultApplicationMenuItems (bool enabled) override
+    {
+        SetAutoGenerateDefaultAppMenuItems(!enabled);
+        return S_OK;
+    }
 };
 
 /// See "Using POSIX Threads in a Cocoa Application" section here:
@@ -310,3 +317,13 @@ CGFloat PrimaryDisplayHeight()
 {
   return NSMaxY([[[NSScreen screens] firstObject] frame]);
 }
+
+void SetAutoGenerateDefaultAppMenuItems (bool enabled)
+{
+    s_generateDefaultAppMenuItems = enabled;
+}
+
+bool GetAutoGenerateDefaultAppMenuItems ()
+{
+    return s_generateDefaultAppMenuItems;
+}

native/Avalonia.Native/src/OSX/menu.mm

@@ -445,47 +445,50 @@ extern void SetAppMenu (NSString* appName, IAvnMenu* menu)
         
         auto appMenu  = [s_appMenuItem submenu];
         
-        [appMenu addItem:[NSMenuItem separatorItem]];
+        if(GetAutoGenerateDefaultAppMenuItems())
-        
+        {
-        // Services item and menu
+            [appMenu addItem:[NSMenuItem separatorItem]];
-        auto servicesItem = [[NSMenuItem alloc] init];
+            
-        servicesItem.title = @"Services";
+            // Services item and menu
-        NSMenu *servicesMenu = [[NSMenu alloc] initWithTitle:@"Services"];
+            auto servicesItem = [[NSMenuItem alloc] init];
-        servicesItem.submenu = servicesMenu;
+            servicesItem.title = @"Services";
-        [NSApplication sharedApplication].servicesMenu = servicesMenu;
+            NSMenu *servicesMenu = [[NSMenu alloc] initWithTitle:@"Services"];
-        [appMenu addItem:servicesItem];
+            servicesItem.submenu = servicesMenu;
-        
+            [NSApplication sharedApplication].servicesMenu = servicesMenu;
-        [appMenu addItem:[NSMenuItem separatorItem]];
+            [appMenu addItem:servicesItem];
-        
+            
-        // Hide Application
+            [appMenu addItem:[NSMenuItem separatorItem]];
-        auto hideItem = [[NSMenuItem alloc] initWithTitle:[@"Hide " stringByAppendingString:appName] action:@selector(hide:) keyEquivalent:@"h"];
+            
-        
+            // Hide Application
-        [appMenu addItem:hideItem];
+            auto hideItem = [[NSMenuItem alloc] initWithTitle:[@"Hide " stringByAppendingString:appName] action:@selector(hide:) keyEquivalent:@"h"];
-        
+            
-        // Hide Others
+            [appMenu addItem:hideItem];
-        auto hideAllOthersItem = [[NSMenuItem alloc] initWithTitle:@"Hide Others"
+            
-                                                       action:@selector(hideOtherApplications:)
+            // Hide Others
-                                                keyEquivalent:@"h"];
+            auto hideAllOthersItem = [[NSMenuItem alloc] initWithTitle:@"Hide Others"
-        
+                                                           action:@selector(hideOtherApplications:)
-        hideAllOthersItem.keyEquivalentModifierMask = NSEventModifierFlagCommand | NSEventModifierFlagOption;
+                                                    keyEquivalent:@"h"];
-        [appMenu addItem:hideAllOthersItem];
+            
-        
+            hideAllOthersItem.keyEquivalentModifierMask = NSEventModifierFlagCommand | NSEventModifierFlagOption;
-        // Show All
+            [appMenu addItem:hideAllOthersItem];
-        auto showAllItem = [[NSMenuItem alloc] initWithTitle:@"Show All"
+            
-                                                 action:@selector(unhideAllApplications:)
+            // Show All
-                                          keyEquivalent:@""];
+            auto showAllItem = [[NSMenuItem alloc] initWithTitle:@"Show All"
-        
+                                                     action:@selector(unhideAllApplications:)
-        [appMenu addItem:showAllItem];
+                                              keyEquivalent:@""];
-        
+            
-        [appMenu addItem:[NSMenuItem separatorItem]];
+            [appMenu addItem:showAllItem];
-        
+            
-        // Quit Application
+            [appMenu addItem:[NSMenuItem separatorItem]];
-        auto quitItem = [[NSMenuItem alloc] init];
+            
-        quitItem.title = [@"Quit " stringByAppendingString:appName];
+            // Quit Application
-        quitItem.keyEquivalent = @"q";
+            auto quitItem = [[NSMenuItem alloc] init];
-        quitItem.target = [AvnWindow class];
+            quitItem.title = [@"Quit " stringByAppendingString:appName];
-        quitItem.action = @selector(closeAll);
+            quitItem.keyEquivalent = @"q";
-        [appMenu addItem:quitItem];
+            quitItem.target = [AvnWindow class];
+            quitItem.action = @selector(closeAll);
+            [appMenu addItem:quitItem];
+        }
     }
     else
     {

src/Avalonia.Animation/Animation.cs

@@ -22,7 +22,7 @@ namespace Avalonia.Animation
         /// </summary>
         public static readonly DirectProperty<Animation, TimeSpan> DurationProperty =
             AvaloniaProperty.RegisterDirect<Animation, TimeSpan>(
-                nameof(_duration),
+                nameof(Duration),
                 o => o._duration,
                 (o, v) => o._duration = v);
 
@@ -31,7 +31,7 @@ namespace Avalonia.Animation
         /// </summary>
         public static readonly DirectProperty<Animation, IterationCount> IterationCountProperty =
             AvaloniaProperty.RegisterDirect<Animation, IterationCount>(
-                nameof(_iterationCount),
+                nameof(IterationCount),
                 o => o._iterationCount,
                 (o, v) => o._iterationCount = v);
 
@@ -40,7 +40,7 @@ namespace Avalonia.Animation
         /// </summary>
         public static readonly DirectProperty<Animation, PlaybackDirection> PlaybackDirectionProperty =
             AvaloniaProperty.RegisterDirect<Animation, PlaybackDirection>(
-                nameof(_playbackDirection),
+                nameof(PlaybackDirection),
                 o => o._playbackDirection,
                 (o, v) => o._playbackDirection = v);
 
@@ -49,7 +49,7 @@ namespace Avalonia.Animation
         /// </summary>
         public static readonly DirectProperty<Animation, FillMode> FillModeProperty =
             AvaloniaProperty.RegisterDirect<Animation, FillMode>(
-                nameof(_fillMode),
+                nameof(FillMode),
                 o => o._fillMode,
                 (o, v) => o._fillMode = v);
 
@@ -58,7 +58,7 @@ namespace Avalonia.Animation
         /// </summary>
         public static readonly DirectProperty<Animation, Easing> EasingProperty =
             AvaloniaProperty.RegisterDirect<Animation, Easing>(
-                nameof(_easing),
+                nameof(Easing),
                 o => o._easing,
                 (o, v) => o._easing = v);
 
@@ -67,7 +67,7 @@ namespace Avalonia.Animation
         /// </summary>
         public static readonly DirectProperty<Animation, TimeSpan> DelayProperty =
             AvaloniaProperty.RegisterDirect<Animation, TimeSpan>(
-                nameof(_delay),
+                nameof(Delay),
                 o => o._delay,
                 (o, v) => o._delay = v);
 
@@ -76,7 +76,7 @@ namespace Avalonia.Animation
         /// </summary>
         public static readonly DirectProperty<Animation, TimeSpan> DelayBetweenIterationsProperty =
             AvaloniaProperty.RegisterDirect<Animation, TimeSpan>(
-                nameof(_delayBetweenIterations),
+                nameof(DelayBetweenIterations),
                 o => o._delayBetweenIterations,
                 (o, v) => o._delayBetweenIterations = v);
 
@@ -85,7 +85,7 @@ namespace Avalonia.Animation
         /// </summary>
         public static readonly DirectProperty<Animation, double> SpeedRatioProperty =
             AvaloniaProperty.RegisterDirect<Animation, double>(
-                nameof(_speedRatio),
+                nameof(SpeedRatio),
                 o => o._speedRatio,
                 (o, v) => o._speedRatio = v,
                 defaultBindingMode: BindingMode.TwoWay);

src/Avalonia.Controls.DataGrid/DataGridTemplateColumn.cs

@@ -8,6 +8,7 @@ using Avalonia.Controls.Utils;
 using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Media;
+using Avalonia.Metadata;
 using Avalonia.Utilities;
 
 namespace Avalonia.Controls
@@ -22,6 +23,7 @@ namespace Avalonia.Controls
                 o => o.CellTemplate,
                 (o, v) => o.CellTemplate = v);
 
+        [Content]
         public IDataTemplate CellTemplate
         {
             get { return _cellTemplate; }

src/Avalonia.Controls/ComboBox.cs

@@ -10,6 +10,7 @@ using Avalonia.Interactivity;
 using Avalonia.Layout;
 using Avalonia.LogicalTree;
 using Avalonia.Media;
+using Avalonia.Threading;
 using Avalonia.VisualTree;
 
 namespace Avalonia.Controls
@@ -76,6 +77,14 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<VerticalAlignment> VerticalContentAlignmentProperty =
             ContentControl.VerticalContentAlignmentProperty.AddOwner<ComboBox>();
 
+        /// <summary>
+        /// Defines the <see cref="IsTextSearchEnabled"/> property.
+        /// </summary>
+        public static readonly StyledProperty<bool> IsTextSearchEnabledProperty =
+            AvaloniaProperty.Register<ComboBox, bool>(nameof(IsTextSearchEnabled), true);
+
+        private string _textSearchTerm = string.Empty;
+        private DispatcherTimer _textSearchTimer;
         private bool _isDropDownOpen;
         private Popup _popup;
         private object _selectionBoxItem;
@@ -164,6 +173,15 @@ namespace Avalonia.Controls
             set { SetValue(VerticalContentAlignmentProperty, value); }
         }
 
+        /// <summary>
+        /// Gets or sets a value that specifies whether a user can jump to a value by typing.
+        /// </summary>
+        public bool IsTextSearchEnabled
+        {
+            get { return GetValue(IsTextSearchEnabledProperty); }
+            set { SetValue(IsTextSearchEnabledProperty, value); }
+        }
+
         /// <inheritdoc/>
         protected override IItemContainerGenerator CreateItemContainerGenerator()
         {
@@ -229,6 +247,32 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <inheritdoc />
+        protected override void OnTextInput(TextInputEventArgs e)
+        {
+            if (!IsTextSearchEnabled || e.Handled)
+                return;
+
+            StopTextSearchTimer();
+
+            _textSearchTerm += e.Text;
+
+            bool match(ItemContainerInfo info) => 
+                info.ContainerControl is IContentControl control &&
+                control.Content?.ToString()?.StartsWith(_textSearchTerm, StringComparison.OrdinalIgnoreCase) == true;
+
+            var info = ItemContainerGenerator.Containers.FirstOrDefault(match);
+
+            if (info != null)
+            {
+                SelectedIndex = info.Index;
+            }
+
+            StartTextSearchTimer();
+
+            e.Handled = true;
+        }
+
         /// <inheritdoc/>
         protected override void OnPointerWheelChanged(PointerWheelEventArgs e)
         {
@@ -426,5 +470,31 @@ namespace Avalonia.Controls
 
             SelectedIndex = prev;
         }
+
+        private void StartTextSearchTimer()
+        {
+            _textSearchTimer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(1) };
+            _textSearchTimer.Tick += TextSearchTimer_Tick;
+            _textSearchTimer.Start();
+        }
+
+        private void StopTextSearchTimer()
+        {
+            if (_textSearchTimer == null)
+            {
+                return;
+            }
+
+            _textSearchTimer.Stop();
+            _textSearchTimer.Tick -= TextSearchTimer_Tick;
+
+            _textSearchTimer = null;
+        }
+
+        private void TextSearchTimer_Tick(object sender, EventArgs e)
+        {
+            _textSearchTerm = string.Empty;
+            StopTextSearchTimer();
+        }
     }
 }

src/Avalonia.Controls/Generators/TabItemContainerGenerator.cs

@@ -1,4 +1,10 @@
+using System;
+using System.Collections.Generic;
 using Avalonia.Controls.Primitives;
+using Avalonia.Controls.Templates;
+using Avalonia.LogicalTree;
+using Avalonia.Reactive;
+using Avalonia.VisualTree;
 
 namespace Avalonia.Controls.Generators
 {    
@@ -16,11 +22,15 @@ namespace Avalonia.Controls.Generators
         {
             var tabItem = (TabItem)base.CreateContainer(item);
 
-            tabItem[~TabControl.TabStripPlacementProperty] = Owner[~TabControl.TabStripPlacementProperty];
+            tabItem.Bind(TabItem.TabStripPlacementProperty, new OwnerBinding<Dock>(
+                tabItem,
+                TabControl.TabStripPlacementProperty));
 
             if (tabItem.HeaderTemplate == null)
             {
-                tabItem[~HeaderedContentControl.HeaderTemplateProperty] = Owner[~ItemsControl.ItemTemplateProperty];
+                tabItem.Bind(TabItem.HeaderTemplateProperty, new OwnerBinding<IDataTemplate>(
+                    tabItem,
+                    TabControl.ItemTemplateProperty));
             }
 
             if (tabItem.Header == null)
@@ -40,10 +50,49 @@ namespace Avalonia.Controls.Generators
 
             if (!(tabItem.Content is IControl))
             {
-                tabItem[~ContentControl.ContentTemplateProperty] = Owner[~TabControl.ContentTemplateProperty];
+                tabItem.Bind(TabItem.ContentTemplateProperty, new OwnerBinding<IDataTemplate>(
+                    tabItem,
+                    TabControl.ContentTemplateProperty));
             }
 
             return tabItem;
         }
+
+        private class OwnerBinding<T> : SingleSubscriberObservableBase<T>
+        {
+            private readonly TabItem _item;
+            private readonly StyledProperty<T> _ownerProperty;
+            private IDisposable _ownerSubscription;
+            private IDisposable _propertySubscription;
+
+            public OwnerBinding(TabItem item, StyledProperty<T> ownerProperty)
+            {
+                _item = item;
+                _ownerProperty = ownerProperty;
+            }
+
+            protected override void Subscribed()
+            {
+                _ownerSubscription = ControlLocator.Track(_item, 0, typeof(TabControl)).Subscribe(OwnerChanged);
+            }
+
+            protected override void Unsubscribed()
+            {
+                _ownerSubscription?.Dispose();
+                _ownerSubscription = null;
+            }
+
+            private void OwnerChanged(ILogical c)
+            {
+                _propertySubscription?.Dispose();
+                _propertySubscription = null;
+
+                if (c is TabControl tabControl)
+                {
+                    _propertySubscription = tabControl.GetObservable(_ownerProperty)
+                        .Subscribe(x => PublishNext(x));
+                }
+            }
+        }
     }
 }

src/Avalonia.Layout/UniformGridLayout.cs

@@ -447,7 +447,7 @@ namespace Avalonia.Layout
             // and only use the layout when to clear it when it's done.
             gridState.EnsureFirstElementOwnership(context);
 
-            return new Size(desiredSize.Width, desiredSize.Height);
+            return desiredSize;
         }
 
         protected internal override Size ArrangeOverride(VirtualizingLayoutContext context, Size finalSize)

src/Avalonia.Layout/UniformGridLayoutState.cs

@@ -44,7 +44,7 @@ namespace Avalonia.Layout
             Size availableSize,
             VirtualizingLayoutContext context,
             double layoutItemWidth,
-            double LayoutItemHeight,
+            double layoutItemHeight,
             UniformGridLayoutItemsStretch stretch,
             Orientation orientation,
             double minRowSpacing,
@@ -63,7 +63,7 @@ namespace Avalonia.Layout
                 if (realizedElement != null)
                 {
                     realizedElement.Measure(availableSize);
-                    SetSize(realizedElement, layoutItemWidth, LayoutItemHeight, availableSize, stretch, orientation, minRowSpacing, minColumnSpacing, maxItemsPerLine);
+                    SetSize(realizedElement, layoutItemWidth, layoutItemHeight, availableSize, stretch, orientation, minRowSpacing, minColumnSpacing, maxItemsPerLine);
                     _cachedFirstElement = null;
                 }
                 else
@@ -78,7 +78,7 @@ namespace Avalonia.Layout
 
                     _cachedFirstElement.Measure(availableSize);
 
-                    SetSize(_cachedFirstElement, layoutItemWidth, LayoutItemHeight, availableSize, stretch, orientation, minRowSpacing, minColumnSpacing, maxItemsPerLine);
+                    SetSize(_cachedFirstElement, layoutItemWidth, layoutItemHeight, availableSize, stretch, orientation, minRowSpacing, minColumnSpacing, maxItemsPerLine);
 
                     // See if we can move ownership to the flow algorithm. If we can, we do not need a local cache.
                     bool added = FlowAlgorithm.TryAddElement0(_cachedFirstElement);
@@ -93,7 +93,7 @@ namespace Avalonia.Layout
         private void SetSize(
             ILayoutable element,
             double layoutItemWidth,
-            double LayoutItemHeight,
+            double layoutItemHeight,
             Size availableSize,
             UniformGridLayoutItemsStretch stretch,
             Orientation orientation,
@@ -107,7 +107,7 @@ namespace Avalonia.Layout
             }
 
             EffectiveItemWidth = (double.IsNaN(layoutItemWidth) ? element.DesiredSize.Width : layoutItemWidth);
-            EffectiveItemHeight = (double.IsNaN(LayoutItemHeight) ? element.DesiredSize.Height : LayoutItemHeight);
+            EffectiveItemHeight = (double.IsNaN(layoutItemHeight) ? element.DesiredSize.Height : layoutItemHeight);
 
             var availableSizeMinor = orientation == Orientation.Horizontal ? availableSize.Width : availableSize.Height;
             var minorItemSpacing = orientation == Orientation.Vertical ? minRowSpacing : minColumnSpacing;

src/Avalonia.Native/AvaloniaNativePlatform.cs

@@ -92,6 +92,8 @@ namespace Avalonia.Native
                 var macOpts = AvaloniaLocator.Current.GetService<MacOSPlatformOptions>();
 
                 _factory.MacOptions.SetShowInDock(macOpts?.ShowInDock != false ? 1 : 0);
+                _factory.MacOptions.SetDisableDefaultApplicationMenuItems(
+                    macOpts?.DisableDefaultApplicationMenuItems == true ? 1 : 0);
             }
 
             AvaloniaLocator.CurrentMutable

src/Avalonia.Native/AvaloniaNativePlatformExtensions.cs

@@ -38,5 +38,7 @@ namespace Avalonia
     public class MacOSPlatformOptions
     {
         public bool ShowInDock { get; set; } = true;
+        
+        public bool DisableDefaultApplicationMenuItems { get; set; }
     }
 }

src/Avalonia.Native/avn.idl

@@ -528,6 +528,7 @@ interface IAvnMacOptions : IUnknown
 {
      HRESULT SetShowInDock(int show);
      HRESULT SetApplicationTitle(char* utf8string);
+     HRESULT SetDisableDefaultApplicationMenuItems(bool enabled);
 }
 
 [uuid(04c1b049-1f43-418a-9159-cae627ec1367)]

src/Avalonia.Themes.Default/MenuItem.xaml

@@ -59,8 +59,7 @@
                   Grid.Column="4"/>
             <Popup Name="PART_Popup"
                    PlacementMode="Right"
-                   IsLightDismissEnabled="True"
+                   IsLightDismissEnabled="False"
-                   OverlayInputPassThroughElement="{Binding $parent[MenuItem]}"
                    IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}">
               <Border Background="{TemplateBinding Background}"
                       BorderBrush="{DynamicResource ThemeBorderMidBrush}"

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

@@ -112,9 +112,8 @@
           <Popup Name="PART_Popup"
                  WindowManagerAddShadowHint="False"
                  PlacementMode="Right"
-                 OverlayInputPassThroughElement="{Binding $parent[MenuItem]}"
                  HorizontalOffset="{DynamicResource MenuFlyoutSubItemPopupHorizontalOffset}"
-                 IsLightDismissEnabled="True"
+                 IsLightDismissEnabled="False"
                  IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}">
             <Border Background="{DynamicResource MenuFlyoutPresenterBackground}"
                     BorderBrush="{DynamicResource MenuFlyoutPresenterBorderBrush}"

tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs

@@ -1,7 +1,9 @@
+using System.Linq;
 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;
@@ -137,5 +139,39 @@ namespace Avalonia.Controls.UnitTests
                 Assert.True(other.IsFocused);
             }
         }
+
+        [Theory]
+        [InlineData(-1, 2, "c", "A item", "B item", "C item")]
+        [InlineData(0, 1, "b", "A item", "B item", "C item")]
+        [InlineData(2, 2, "x", "A item", "B item", "C item")]
+        public void TextSearch_Should_Have_Expected_SelectedIndex(
+            int initialSelectedIndex,
+            int expectedSelectedIndex,
+            string searchTerm,
+            params string[] items)
+        {
+            using (UnitTestApplication.Start(TestServices.MockThreadingInterface))
+            {
+                var target = new ComboBox
+                {
+                    Template = GetTemplate(),                    
+                    Items = items.Select(x => new ComboBoxItem { Content = x })
+                };
+
+                target.ApplyTemplate();
+                target.Presenter.ApplyTemplate();
+                target.SelectedIndex = initialSelectedIndex;
+
+                var args = new TextInputEventArgs
+                {
+                    Text = searchTerm,
+                    RoutedEvent = InputElement.TextInputEvent
+                };
+
+                target.RaiseEvent(args);
+
+                Assert.Equal(expectedSelectedIndex, target.SelectedIndex);
+            }
+        }
     }
 }

tests/Avalonia.Controls.UnitTests/TabControlTests.cs

@@ -374,6 +374,7 @@ namespace Avalonia.Controls.UnitTests
                     new TextBlock { Tag = "bar", Text = x }),
                 Items = new[] { "Foo" },
             };
+            var root = new TestRoot(target);
 
             ApplyTemplate(target);
             ((ContentPresenter)target.ContentPart).UpdateChild();

tests/Avalonia.LeakTests/ControlTests.cs

@@ -313,7 +313,6 @@ namespace Avalonia.LeakTests
             }
         }
 
-
         [Fact]
         public void Slider_Is_Freed()
         {
@@ -347,6 +346,43 @@ namespace Avalonia.LeakTests
             }
         }
 
+        [Fact]
+        public void TabItem_Is_Freed()
+        {
+            using (Start())
+            {
+                Func<Window> run = () =>
+                {
+                    var window = new Window
+                    {
+                        Content = new TabControl
+                        {
+                            Items = new[] { new TabItem() }
+                        }
+                    };
+
+                    window.Show();
+
+                    // Do a layout and make sure that TabControl and TabItem gets added to visual tree.
+                    window.LayoutManager.ExecuteInitialLayoutPass();
+                    var tabControl = Assert.IsType<TabControl>(window.Presenter.Child);
+                    Assert.IsType<TabItem>(tabControl.Presenter.Panel.Children[0]);
+
+                    // Clear the items and ensure the TabItem is removed.
+                    tabControl.Items = null;
+                    window.LayoutManager.ExecuteLayoutPass();
+                    Assert.Empty(tabControl.Presenter.Panel.Children);
+
+                    return window;
+                };
+
+                var result = run();
+
+                dotMemory.Check(memory =>
+                    Assert.Equal(0, memory.GetObjects(where => where.Type.Is<TabItem>()).ObjectsCount));
+            }
+        }
+
         [Fact]
         public void RendererIsDisposed()
         {

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

@@ -117,9 +117,11 @@ namespace Avalonia.Markup.UnitTests.Parsers
             var result = run();
             result.Item1.Subscribe(x => { });
 
-            GC.Collect();
+            // Mono trickery
+            GC.Collect(2);
             GC.WaitForPendingFinalizers();
-            GC.Collect();
+            GC.WaitForPendingFinalizers();
+            GC.Collect(2);
 
             Assert.Null(result.Item2.Target);
         }