Merge branch 'master' into fix-nested-popups

build/Microsoft.Reactive.Testing.props

@@ -1,5 +1,5 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="Microsoft.Reactive.Testing" Version="4.0.0" />
+    <PackageReference Include="Microsoft.Reactive.Testing" Version="4.1.6" />
   </ItemGroup>
 </Project>

build/ReactiveUI.props

@@ -1,5 +1,5 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="reactiveui" Version="9.0.1" />
+    <PackageReference Include="ReactiveUI" Version="10.3.6" />
   </ItemGroup>
 </Project>

build/Rx.props

@@ -1,5 +1,5 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="System.Reactive" Version="4.0.0" />
+    <PackageReference Include="System.Reactive" Version="4.1.6" />
   </ItemGroup>
 </Project>

build/System.Memory.props

@@ -1,5 +1,5 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="System.Memory" Version="4.5.1" />
+    <PackageReference Include="System.Memory" Version="4.5.3" />
   </ItemGroup>
 </Project>

dirs.proj

@@ -8,7 +8,8 @@
     <ProjectReference Remove="src/Markup/Avalonia.Markup.Xaml/PortableXaml/**/*.*proj" />
     <ProjectReference Remove="src/Markup/Avalonia.Markup.Xaml/XamlIl/**/*.*proj" />
   </ItemGroup>
-  <ItemGroup Condition="!Exists('$(MSBuildExtensionsPath)\Xamarin\Android')">
+  <!--<ItemGroup Condition="!Exists('$(MSBuildExtensionsPath)\Xamarin\Android')">-->
+  <ItemGroup>
     <ProjectReference Remove="src/Android/**/*.*proj" />
     <ProjectReference Remove="samples/ControlCatalog.Android/ControlCatalog.Android.csproj" />
   </ItemGroup>

samples/BindingDemo/ViewModels/MainWindowViewModel.cs

@@ -1,10 +1,11 @@
 using System;
 using System.Collections.ObjectModel;
 using System.Linq;
-using ReactiveUI;
+using System.Reactive;
 using System.Reactive.Linq;
 using System.Threading.Tasks;
 using System.Threading;
+using ReactiveUI;
 
 namespace BindingDemo.ViewModels
 {
@@ -56,7 +57,7 @@ namespace BindingDemo.ViewModels
 
         public ObservableCollection<TestItem> Items { get; }
         public ObservableCollection<TestItem> SelectedItems { get; }
-        public ReactiveCommand ShuffleItems { get; }
+        public ReactiveCommand<Unit, Unit> ShuffleItems { get; }
 
         public string BooleanString
         {
@@ -89,7 +90,7 @@ namespace BindingDemo.ViewModels
         }
 
         public IObservable<string> CurrentTimeObservable { get; }
-        public ReactiveCommand StringValueCommand { get; }
+        public ReactiveCommand<object, Unit> StringValueCommand { get; }
 
         public DataAnnotationsErrorViewModel DataAnnotationsValidation { get; } = new DataAnnotationsErrorViewModel();
         public ExceptionErrorViewModel ExceptionDataValidation { get; } = new ExceptionErrorViewModel();

samples/RenderDemo/ViewModels/MainWindowViewModel.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Reactive;
 using ReactiveUI;
 
 namespace RenderDemo.ViewModels
@@ -26,7 +27,7 @@ namespace RenderDemo.ViewModels
             set { this.RaiseAndSetIfChanged(ref drawFps, value); }
         }
 
-        public ReactiveCommand ToggleDrawDirtyRects { get; }
-        public ReactiveCommand ToggleDrawFps { get; }
+        public ReactiveCommand<Unit, bool> ToggleDrawDirtyRects { get; }
+        public ReactiveCommand<Unit, bool> ToggleDrawFps { get; }
     }
 }

samples/VirtualizationDemo/ViewModels/MainWindowViewModel.cs

@@ -4,10 +4,10 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reactive;
 using Avalonia.Collections;
 using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
-using ReactiveUI.Legacy;
 using ReactiveUI;
 using Avalonia.Layout;
 
@@ -18,7 +18,7 @@ namespace VirtualizationDemo.ViewModels
         private int _itemCount = 200;
         private string _newItemString = "New Item";
         private int _newItemIndex;
-        private IReactiveList<ItemViewModel> _items;
+        private AvaloniaList<ItemViewModel> _items;
         private string _prefix = "Item";
         private ScrollBarVisibility _horizontalScrollBarVisibility = ScrollBarVisibility.Auto;
         private ScrollBarVisibility _verticalScrollBarVisibility = ScrollBarVisibility.Auto;
@@ -54,7 +54,7 @@ namespace VirtualizationDemo.ViewModels
         public AvaloniaList<ItemViewModel> SelectedItems { get; } 
             = new AvaloniaList<ItemViewModel>();
 
-        public IReactiveList<ItemViewModel> Items
+        public AvaloniaList<ItemViewModel> Items
         {
             get { return _items; }
             private set { this.RaiseAndSetIfChanged(ref _items, value); }
@@ -93,11 +93,11 @@ namespace VirtualizationDemo.ViewModels
         public IEnumerable<ItemVirtualizationMode> VirtualizationModes => 
             Enum.GetValues(typeof(ItemVirtualizationMode)).Cast<ItemVirtualizationMode>();
 
-        public ReactiveCommand AddItemCommand { get; private set; }
-        public ReactiveCommand RecreateCommand { get; private set; }
-        public ReactiveCommand RemoveItemCommand { get; private set; }
-        public ReactiveCommand SelectFirstCommand { get; private set; }
-        public ReactiveCommand SelectLastCommand { get; private set; }
+        public ReactiveCommand<Unit, Unit> AddItemCommand { get; private set; }
+        public ReactiveCommand<Unit, Unit> RecreateCommand { get; private set; }
+        public ReactiveCommand<Unit, Unit> RemoveItemCommand { get; private set; }
+        public ReactiveCommand<Unit, Unit> SelectFirstCommand { get; private set; }
+        public ReactiveCommand<Unit, Unit> SelectLastCommand { get; private set; }
 
         public void RandomizeSize()
         {
@@ -123,7 +123,7 @@ namespace VirtualizationDemo.ViewModels
             {
                 var items = Enumerable.Range(0, count)
                     .Select(x => new ItemViewModel(x));
-                Items = new ReactiveList<ItemViewModel>(items);
+                Items = new AvaloniaList<ItemViewModel>(items);
             }
             else if (count > Items.Count)
             {
@@ -162,7 +162,7 @@ namespace VirtualizationDemo.ViewModels
             _prefix = _prefix == "Item" ? "Recreated" : "Item";
             var items = Enumerable.Range(0, _itemCount)
                 .Select(x => new ItemViewModel(x, _prefix));
-            Items = new ReactiveList<ItemViewModel>(items);
+            Items = new AvaloniaList<ItemViewModel>(items);
         }
 
         private void SelectItem(int index)

src/Avalonia.Controls/WrapPanel.cs

@@ -15,7 +15,7 @@ namespace Avalonia.Controls
     /// Positions child elements in sequential position from left to right, 
     /// breaking content to the next line at the edge of the containing box. 
     /// Subsequent ordering happens sequentially from top to bottom or from right to left, 
-    /// depending on the value of the Orientation property.
+    /// depending on the value of the <see cref="Orientation"/> property.
     /// </summary>
     public class WrapPanel : Panel, INavigableContainer
     {
@@ -25,6 +25,18 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<Orientation> OrientationProperty =
             AvaloniaProperty.Register<WrapPanel, Orientation>(nameof(Orientation), defaultValue: Orientation.Horizontal);
 
+        /// <summary>
+        /// Defines the <see cref="ItemWidth"/> property.
+        /// </summary>
+        public static readonly StyledProperty<double> ItemWidthProperty =
+            AvaloniaProperty.Register<WrapPanel, double>(nameof(ItemWidth), double.NaN);
+
+        /// <summary>
+        /// Defines the <see cref="ItemHeight"/> property.
+        /// </summary>
+        public static readonly StyledProperty<double> ItemHeightProperty =
+            AvaloniaProperty.Register<WrapPanel, double>(nameof(ItemHeight), double.NaN);
+
         /// <summary>
         /// Initializes static members of the <see cref="WrapPanel"/> class.
         /// </summary>
@@ -42,6 +54,24 @@ namespace Avalonia.Controls
             set { SetValue(OrientationProperty, value); }
         }
 
+        /// <summary>
+        /// Gets or sets the width of all items in the WrapPanel.
+        /// </summary>
+        public double ItemWidth
+        {
+            get { return GetValue(ItemWidthProperty); }
+            set { SetValue(ItemWidthProperty, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the height of all items in the WrapPanel.
+        /// </summary>
+        public double ItemHeight
+        {
+            get { return GetValue(ItemHeightProperty); }
+            set { SetValue(ItemHeightProperty, value); }
+        }
+
         /// <summary>
         /// Gets the next control in the specified direction.
         /// </summary>
@@ -51,7 +81,9 @@ namespace Avalonia.Controls
         /// <returns>The control.</returns>
         IInputElement INavigableContainer.GetControl(NavigationDirection direction, IInputElement from, bool wrap)
         {
-            var horiz = Orientation == Orientation.Horizontal;
+            var orientation = Orientation;
+            var children = Children;
+            bool horiz = orientation == Orientation.Horizontal;
             int index = Children.IndexOf((IControl)from);
 
             switch (direction)
@@ -60,7 +92,7 @@ namespace Avalonia.Controls
                     index = 0;
                     break;
                 case NavigationDirection.Last:
-                    index = Children.Count - 1;
+                    index = children.Count - 1;
                     break;
                 case NavigationDirection.Next:
                     ++index;
@@ -82,9 +114,9 @@ namespace Avalonia.Controls
                     break;
             }
 
-            if (index >= 0 && index < Children.Count)
+            if (index >= 0 && index < children.Count)
             {
-                return Children[index];
+                return children[index];
             }
             else
             {
@@ -95,116 +127,140 @@ namespace Avalonia.Controls
         /// <inheritdoc/>
         protected override Size MeasureOverride(Size constraint)
         {
-            var curLineSize = new UVSize(Orientation);
-            var panelSize = new UVSize(Orientation);
-            var uvConstraint = new UVSize(Orientation, constraint.Width, constraint.Height);
-
-            var childConstraint = new Size(constraint.Width, constraint.Height);
-
-            for (int i = 0, count = Children.Count; i < count; i++)
+            double itemWidth = ItemWidth;
+            double itemHeight = ItemHeight;
+            var orientation = Orientation;
+            var children = Children;
+            var curLineSize = new UVSize(orientation);
+            var panelSize = new UVSize(orientation);
+            var uvConstraint = new UVSize(orientation, constraint.Width, constraint.Height);
+            bool itemWidthSet = !double.IsNaN(itemWidth);
+            bool itemHeightSet = !double.IsNaN(itemHeight);
+
+            var childConstraint = new Size(
+                itemWidthSet ? itemWidth : constraint.Width,
+                itemHeightSet ? itemHeight : constraint.Height);
+            
+            for (int i = 0, count = children.Count; i < count; i++)
             {
-                var child = Children[i];
-                if (child == null) continue;
-
-                //Flow passes its own constrint to children
-                child.Measure(childConstraint);
-
-                //this is the size of the child in UV space
-                var sz = new UVSize(Orientation, child.DesiredSize.Width, child.DesiredSize.Height);
-
-                if (MathUtilities.GreaterThan(curLineSize.U + sz.U, uvConstraint.U)) //need to switch to another line
+                var child = children[i];
+                if (child != null)
                 {
-                    panelSize.U = Max(curLineSize.U, panelSize.U);
-                    panelSize.V += curLineSize.V;
-                    curLineSize = sz;
+                    // Flow passes its own constraint to children
+                    child.Measure(childConstraint);
+
+                    // This is the size of the child in UV space
+                    var sz = new UVSize(orientation,
+                        itemWidthSet ? itemWidth : child.DesiredSize.Width,
+                        itemHeightSet ? itemHeight : child.DesiredSize.Height);
 
-                    if (MathUtilities.GreaterThan(sz.U, uvConstraint.U)) //the element is wider then the constrint - give it a separate line                    
+                    if (MathUtilities.GreaterThan(curLineSize.U + sz.U, uvConstraint.U)) // Need to switch to another line
                     {
-                        panelSize.U = Max(sz.U, panelSize.U);
-                        panelSize.V += sz.V;
-                        curLineSize = new UVSize(Orientation);
+                        panelSize.U = Max(curLineSize.U, panelSize.U);
+                        panelSize.V += curLineSize.V;
+                        curLineSize = sz;
+
+                        if (MathUtilities.GreaterThan(sz.U, uvConstraint.U)) // The element is wider then the constraint - give it a separate line                    
+                        {
+                            panelSize.U = Max(sz.U, panelSize.U);
+                            panelSize.V += sz.V;
+                            curLineSize = new UVSize(orientation);
+                        }
+                    }
+                    else // Continue to accumulate a line
+                    {
+                        curLineSize.U += sz.U;
+                        curLineSize.V = Max(sz.V, curLineSize.V);
                     }
-                }
-                else //continue to accumulate a line
-                {
-                    curLineSize.U += sz.U;
-                    curLineSize.V = Max(sz.V, curLineSize.V);
                 }
             }
 
-            //the last line size, if any should be added
+            // The last line size, if any should be added
             panelSize.U = Max(curLineSize.U, panelSize.U);
             panelSize.V += curLineSize.V;
 
-            //go from UV space to W/H space
+            // Go from UV space to W/H space
             return new Size(panelSize.Width, panelSize.Height);
         }
 
         /// <inheritdoc/>
         protected override Size ArrangeOverride(Size finalSize)
         {
+            double itemWidth = ItemWidth;
+            double itemHeight = ItemHeight;
+            var orientation = Orientation;
+            var children = Children;
             int firstInLine = 0;
             double accumulatedV = 0;
-            UVSize curLineSize = new UVSize(Orientation);
-            UVSize uvFinalSize = new UVSize(Orientation, finalSize.Width, finalSize.Height);
-
-            for (int i = 0; i < Children.Count; i++)
+            double itemU = orientation == Orientation.Horizontal ? itemWidth : itemHeight;
+            var curLineSize = new UVSize(orientation);
+            var uvFinalSize = new UVSize(orientation, finalSize.Width, finalSize.Height);
+            bool itemWidthSet = !double.IsNaN(itemWidth);
+            bool itemHeightSet = !double.IsNaN(itemHeight);
+            bool useItemU = orientation == Orientation.Horizontal ? itemWidthSet : itemHeightSet;
+
+            for (int i = 0; i < children.Count; i++)
             {
-                var child = Children[i];
-                if (child == null) continue;
+                var child = children[i];
+                if (child != null)
+                {
+                    var sz = new UVSize(orientation,
+                        itemWidthSet ? itemWidth : child.DesiredSize.Width,
+                        itemHeightSet ? itemHeight : child.DesiredSize.Height);
 
-                var sz = new UVSize(Orientation, child.DesiredSize.Width, child.DesiredSize.Height);
+                    if (MathUtilities.GreaterThan(curLineSize.U + sz.U, uvFinalSize.U)) // Need to switch to another line
+                    {
+                        ArrangeLine(accumulatedV, curLineSize.V, firstInLine, i, useItemU, itemU);
 
-                if (MathUtilities.GreaterThan(curLineSize.U + sz.U, uvFinalSize.U)) //need to switch to another line
-                {
-                    arrangeLine(accumulatedV, curLineSize.V, firstInLine, i);
+                        accumulatedV += curLineSize.V;
+                        curLineSize = sz;
 
-                    accumulatedV += curLineSize.V;
-                    curLineSize = sz;
+                        if (MathUtilities.GreaterThan(sz.U, uvFinalSize.U)) // The element is wider then the constraint - give it a separate line                    
+                        {
+                            // Switch to next line which only contain one element
+                            ArrangeLine(accumulatedV, sz.V, i, ++i, useItemU, itemU);
 
-                    if (MathUtilities.GreaterThan(sz.U, uvFinalSize.U)) //the element is wider then the constraint - give it a separate line                    
+                            accumulatedV += sz.V;
+                            curLineSize = new UVSize(orientation);
+                        }
+                        firstInLine = i;
+                    }
+                    else // Continue to accumulate a line
                     {
-                        //switch to next line which only contain one element
-                        arrangeLine(accumulatedV, sz.V, i, ++i);
-
-                        accumulatedV += sz.V;
-                        curLineSize = new UVSize(Orientation);
+                        curLineSize.U += sz.U;
+                        curLineSize.V = Max(sz.V, curLineSize.V);
                     }
-                    firstInLine = i;
-                }
-                else //continue to accumulate a line
-                {
-                    curLineSize.U += sz.U;
-                    curLineSize.V = Max(sz.V, curLineSize.V);
                 }
             }
 
-            //arrange the last line, if any
-            if (firstInLine < Children.Count)
+            // Arrange the last line, if any
+            if (firstInLine < children.Count)
             {
-                arrangeLine(accumulatedV, curLineSize.V, firstInLine, Children.Count);
+                ArrangeLine(accumulatedV, curLineSize.V, firstInLine, children.Count, useItemU, itemU);
             }
 
             return finalSize;
         }
 
-        private void arrangeLine(double v, double lineV, int start, int end)
+        private void ArrangeLine(double v, double lineV, int start, int end, bool useItemU, double itemU)
         {
+            var orientation = Orientation;
+            var children = Children;
             double u = 0;
-            bool isHorizontal = (Orientation == Orientation.Horizontal);
+            bool isHorizontal = orientation == Orientation.Horizontal;
 
             for (int i = start; i < end; i++)
             {
-                var child = Children[i];
+                var child = children[i];
                 if (child != null)
                 {
-                    UVSize childSize = new UVSize(Orientation, child.DesiredSize.Width, child.DesiredSize.Height);
-                    double layoutSlotU = childSize.U;
+                    var childSize = new UVSize(orientation, child.DesiredSize.Width, child.DesiredSize.Height);
+                    double layoutSlotU = useItemU ? itemU : childSize.U;
                     child.Arrange(new Rect(
-                        (isHorizontal ? u : v),
-                        (isHorizontal ? v : u),
-                        (isHorizontal ? layoutSlotU : lineV),
-                        (isHorizontal ? lineV : layoutSlotU)));
+                        isHorizontal ? u : v,
+                        isHorizontal ? v : u,
+                        isHorizontal ? layoutSlotU : lineV,
+                        isHorizontal ? lineV : layoutSlotU));
                     u += layoutSlotU;
                 }
             }
@@ -232,12 +288,12 @@ namespace Avalonia.Controls
 
             internal double Width
             {
-                get { return (_orientation == Orientation.Horizontal ? U : V); }
+                get { return _orientation == Orientation.Horizontal ? U : V; }
                 set { if (_orientation == Orientation.Horizontal) U = value; else V = value; }
             }
             internal double Height
             {
-                get { return (_orientation == Orientation.Horizontal ? V : U); }
+                get { return _orientation == Orientation.Horizontal ? V : U; }
                 set { if (_orientation == Orientation.Horizontal) V = value; else U = value; }
             }
         }

src/Avalonia.ReactiveUI/AvaloniaActivationForViewFetcher.cs

@@ -27,7 +27,7 @@ namespace Avalonia.ReactiveUI
         /// <summary>
         /// Returns activation observable for activatable Avalonia view.
         /// </summary>
-        public IObservable<bool> GetActivationForView(IActivatable view)
+        public IObservable<bool> GetActivationForView(IActivatableView view)
         {
             if (!(view is IVisual visual)) return Observable.Return(false);
             if (view is WindowBase window) return GetActivationForWindowBase(window);

src/Avalonia.ReactiveUI/RoutedViewHost.cs

@@ -53,7 +53,7 @@ namespace Avalonia.ReactiveUI
     /// ReactiveUI routing documentation website</see> for more info.
     /// </para>
     /// </remarks>
-    public class RoutedViewHost : TransitioningContentControl, IActivatable, IEnableLogger
+    public class RoutedViewHost : TransitioningContentControl, IActivatableView, IEnableLogger
     {
         /// <summary>
         /// <see cref="AvaloniaProperty"/> for the <see cref="Router"/> property.

src/Avalonia.Visuals/Rendering/DeferredRenderer.cs

@@ -540,7 +540,7 @@ namespace Avalonia.Rendering
                     foreach (var visual in _recalculateChildren)
                     {
                         var node = scene.FindNode(visual);
-                        ((VisualNode)node)?.UpdateChildren(scene);
+                        ((VisualNode)node)?.SortChildren(scene);
                     }
 
                     _recalculateChildren.Clear();

src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs

@@ -53,6 +53,16 @@ namespace Avalonia.Rendering.SceneGraph
 
             if (visual.VisualRoot != null)
             {
+                if (node?.Parent != null &&
+                    visual.VisualParent != null &&
+                    node.Parent.Visual != visual.VisualParent)
+                {
+                    // The control has changed parents. Remove the node and recurse into the new parent node.
+                    ((VisualNode)node.Parent).RemoveChild(node);
+                    Deindex(scene, node);
+                    node = (VisualNode)scene.FindNode(visual.VisualParent);
+                }
+
                 if (visual.IsVisible)
                 {
                     // If the node isn't yet part of the scene, find the nearest ancestor that is.

src/Avalonia.Visuals/Rendering/SceneGraph/VisualNode.cs

@@ -174,12 +174,12 @@ namespace Avalonia.Rendering.SceneGraph
 
         /// <summary>
         /// Sorts the <see cref="Children"/> collection according to the order of the visual's
-        /// children and their z-index and removes controls that are no longer children.
+        /// children and their z-index.
         /// </summary>
         /// <param name="scene">The scene that the node is a part of.</param>
-        public void UpdateChildren(Scene scene)
+        public void SortChildren(Scene scene)
         {
-            if (_children == null || _children.Count == 0)
+            if (_children == null || _children.Count <= 1)
             {
                 return;
             }
@@ -193,12 +193,9 @@ namespace Avalonia.Rendering.SceneGraph
                 keys.Add(((long)zIndex << 32) + i);
             }
 
-            var toRemove = _children.ToList();
-
             keys.Sort();
             _children.Clear();
 
-
             foreach (var i in keys)
             {
                 var child = Visual.VisualChildren[(int)(i & 0xffffffff)];
@@ -207,14 +204,8 @@ namespace Avalonia.Rendering.SceneGraph
                 if (node != null)
                 {
                     _children.Add(node);
-                    toRemove.Remove(node);
                 }
             }
-
-            foreach (var node in toRemove)
-            {
-                scene.Remove(node);
-            }
         }
 
         /// <summary>

tests/Avalonia.Controls.UnitTests/WrapPanelTests.cs

@@ -93,5 +93,29 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(new Rect(0, 0, 100, 50), target.Children[0].Bounds);
             Assert.Equal(new Rect(100, 0, 100, 50), target.Children[1].Bounds);
         }
+
+        [Fact]
+        public void Applies_ItemWidth_And_ItemHeight_Properties()
+        {
+            var target = new WrapPanel()
+                        {
+                            Orientation = Orientation.Horizontal,
+                            Width = 50,
+                            ItemWidth = 20,
+                            ItemHeight = 15,
+                            Children =
+                            {
+                                new Border(),
+                                new Border(),
+                            }
+                        };
+
+            target.Measure(Size.Infinity);
+            target.Arrange(new Rect(target.DesiredSize));
+
+            Assert.Equal(new Size(50, 15), target.Bounds.Size);
+            Assert.Equal(new Rect(0, 0, 20, 15), target.Children[0].Bounds);
+            Assert.Equal(new Rect(20, 0, 20, 15), target.Children[1].Bounds);
+        }
     }
 }

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

@@ -120,6 +120,8 @@ namespace Avalonia.Markup.UnitTests.Parsers
             var result = run();
             result.Item1.Subscribe(x => { });
 
+            GC.Collect();
+            GC.WaitForPendingFinalizers();
             GC.Collect();
 
             Assert.Null(result.Item2.Target);

tests/Avalonia.ReactiveUI.UnitTests/AvaloniaActivationForViewFetcherTest.cs

@@ -20,9 +20,9 @@ namespace Avalonia.ReactiveUI.UnitTests
 {
     public class AvaloniaActivationForViewFetcherTest
     {
-        public class TestUserControl : UserControl, IActivatable { }
+        public class TestUserControl : UserControl, IActivatableView { }
 
-        public class TestUserControlWithWhenActivated : UserControl, IActivatable
+        public class TestUserControlWithWhenActivated : UserControl, IActivatableView
         {
             public bool Active { get; private set; }
 
@@ -38,7 +38,7 @@ namespace Avalonia.ReactiveUI.UnitTests
             }
         }
 
-        public class TestWindowWithWhenActivated : Window, IActivatable
+        public class TestWindowWithWhenActivated : Window, IActivatableView
         {
             public bool Active { get; private set; }
 
@@ -54,7 +54,7 @@ namespace Avalonia.ReactiveUI.UnitTests
             }
         }
 
-        public class ActivatableViewModel : ISupportsActivation
+        public class ActivatableViewModel : IActivatableViewModel
         {
             public ViewModelActivator Activator { get; }
 

tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs

@@ -96,6 +96,55 @@ namespace Avalonia.Visuals.UnitTests.Rendering
             Assert.Equal(new List<IVisual> { root, decorator, border, canvas }, result);
         }
 
+        [Fact]
+        public void Should_Add_Dirty_Rect_On_Child_Remove()
+        {
+            var dispatcher = new ImmediateDispatcher();
+            var loop = new Mock<IRenderLoop>();
+
+            Decorator decorator;
+            Border border;
+            var root = new TestRoot
+            {
+                Width = 100,
+                Height= 100,
+                Child = decorator = new Decorator
+                {
+                    Child = border = new Border
+                    {
+                        Width = 50,
+                        Height = 50,
+                        Background = Brushes.Red,
+                    },
+                }
+            };
+
+            root.Measure(Size.Infinity);
+            root.Arrange(new Rect(root.DesiredSize));
+
+            var sceneBuilder = new SceneBuilder();
+            var target = new DeferredRenderer(
+                root,
+                loop.Object,
+                sceneBuilder: sceneBuilder,
+                dispatcher: dispatcher);
+
+            root.Renderer = target;
+            target.Start();
+            RunFrame(target);
+
+            decorator.Child = null;
+
+            RunFrame(target);
+
+            var scene = target.UnitTestScene();
+            var stackNode = scene.FindNode(decorator);
+            var dirty = scene.Layers[0].Dirty.ToList();
+
+            Assert.Equal(1, dirty.Count);
+            Assert.Equal(new Rect(25, 25, 50, 50), dirty[0]);
+        }
+
         [Fact]
         public void Should_Update_VisualNode_Order_On_Child_Remove_Insert()
         {

tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests.cs

@@ -521,8 +521,8 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                 moveFromNode = (VisualNode)scene.FindNode(moveFrom);
                 moveToNode = (VisualNode)scene.FindNode(moveTo);
 
-                moveFromNode.UpdateChildren(scene);
-                moveToNode.UpdateChildren(scene);
+                moveFromNode.SortChildren(scene);
+                moveToNode.SortChildren(scene);
                 sceneBuilder.Update(scene, moveFrom);
                 sceneBuilder.Update(scene, moveTo);
                 sceneBuilder.Update(scene, moveMe);

tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/VisualNodeTests.cs

@@ -99,7 +99,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
             var node = new VisualNode(Mock.Of<IVisual>(), null);
             var scene = new Scene(Mock.Of<IVisual>());
 
-            node.UpdateChildren(scene);
+            node.SortChildren(scene);
         }
     }
 }