Merge remote-tracking branch 'origin/master' into feature/experimental-acrylic-brush

samples/ControlCatalog/Pages/TreeViewPage.xaml

@@ -20,6 +20,7 @@
 
         <Button Command="{Binding AddItemCommand}">Add</Button>
         <Button Command="{Binding RemoveItemCommand}">Remove</Button>
+        <Button Command="{Binding SelectRandomItemCommand}">Select Random</Button>
 
         <ComboBox SelectedIndex="{Binding SelectionMode, Mode=TwoWay}">
           <ComboBoxItem>Single</ComboBoxItem>

samples/ControlCatalog/ViewModels/TreeViewPageViewModel.cs

@@ -23,12 +23,14 @@ namespace ControlCatalog.ViewModels
 
             AddItemCommand = ReactiveCommand.Create(AddItem);
             RemoveItemCommand = ReactiveCommand.Create(RemoveItem);
+            SelectRandomItemCommand = ReactiveCommand.Create(SelectRandomItem);
         }
 
         public ObservableCollection<Node> Items { get; }
         public SelectionModel Selection { get; }
         public ReactiveCommand<Unit, Unit> AddItemCommand { get; }
         public ReactiveCommand<Unit, Unit> RemoveItemCommand { get; }
+        public ReactiveCommand<Unit, Unit> SelectRandomItemCommand { get; }
 
         public SelectionMode SelectionMode
         {
@@ -74,6 +76,15 @@ namespace ControlCatalog.ViewModels
             }
         }
 
+        private void SelectRandomItem()
+        {
+            var random = new Random();
+            var depth = random.Next(4);
+            var indexes = Enumerable.Range(0, 4).Select(x => random.Next(10));
+            var path = new IndexPath(indexes);
+            Selection.SelectedIndex = path;
+        }
+
         private void SelectionChanged(object sender, SelectionModelSelectionChangedEventArgs e)
         {
             var selected = string.Join(",", e.SelectedIndices);

src/Avalonia.Controls/IndexPath.cs

@@ -123,6 +123,26 @@ namespace Avalonia.Controls
             }
         }
 
+        public bool IsAncestorOf(in IndexPath other)
+        {
+            if (other.GetSize() <= GetSize())
+            {
+                return false;
+            }
+
+            var size = GetSize();
+
+            for (int i = 0; i < size; i++)
+            {
+                if (GetAt(i) != other.GetAt(i))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
         public override string ToString()
         {
             if (_path != null)

src/Avalonia.Controls/IndexRange.cs

@@ -132,6 +132,53 @@ namespace Avalonia.Controls
             return result;
         }
 
+        public static int Intersect(
+            IList<IndexRange> ranges,
+            IndexRange range,
+            IList<IndexRange>? removed = null)
+        {
+            var result = 0;
+
+            for (var i = 0; i < ranges.Count && range != s_invalid; ++i)
+            {
+                var existing = ranges[i];
+
+                if (existing.End < range.Begin || existing.Begin > range.End)
+                {
+                    removed?.Add(existing);
+                    ranges.RemoveAt(i--);
+                    result += existing.Count;
+                }
+                else
+                {
+                    if (existing.Begin < range.Begin)
+                    {
+                        var except = new IndexRange(existing.Begin, range.Begin - 1);
+                        removed?.Add(except);
+                        ranges[i] = existing = new IndexRange(range.Begin, existing.End);
+                        result += except.Count;
+                    }
+
+                    if (existing.End > range.End)
+                    {
+                        var except = new IndexRange(range.End + 1, existing.End);
+                        removed?.Add(except);
+                        ranges[i] = new IndexRange(existing.Begin, range.End);
+                        result += except.Count;
+                    }
+                }
+            }
+
+            MergeRanges(ranges);
+
+            if (removed is object)
+            {
+                MergeRanges(removed);
+            }
+
+            return result;
+        }
+
         public static int Remove(
             IList<IndexRange> ranges,
             IndexRange range,

src/Avalonia.Controls/SelectionModel.cs

@@ -46,17 +46,25 @@ namespace Avalonia.Controls
 
                     if (_rootNode.Source != null)
                     {
-                        if (_rootNode.Source != null)
+                        // Temporarily prevent auto-select when switching source.
+                        var restoreAutoSelect = _autoSelect;
+                        _autoSelect = false;
+
+                        try
                         {
                             using (var operation = new Operation(this))
                             {
                                 ClearSelection(resetAnchor: true);
                             }
                         }
+                        finally
+                        {
+                            _autoSelect = restoreAutoSelect;
+                        }
                     }
 
                     _rootNode.Source = value;
-                    ApplyAutoSelect();
+                    ApplyAutoSelect(true);
 
                     RaisePropertyChanged("Source");
 
@@ -114,7 +122,7 @@ namespace Avalonia.Controls
                 if (_autoSelect != value)
                 {
                     _autoSelect = value;
-                    ApplyAutoSelect();
+                    ApplyAutoSelect(true);
                 }
             }
         }
@@ -133,7 +141,7 @@ namespace Avalonia.Controls
                     while (current?.AnchorIndex >= 0)
                     {
                         path.Add(current.AnchorIndex);
-                        current = current.GetAt(current.AnchorIndex, false);
+                        current = current.GetAt(current.AnchorIndex, false, default);
                     }
 
                     anchor = new IndexPath(path);
@@ -188,7 +196,6 @@ namespace Avalonia.Controls
                     using var operation = new Operation(this);
                     ClearSelection(resetAnchor: true);
                     SelectWithPathImpl(value, select: true);
-                    ApplyAutoSelect();
                 }
             }
         }
@@ -384,21 +391,18 @@ namespace Avalonia.Controls
         {
             using var operation = new Operation(this);
             SelectImpl(index, select: false);
-            ApplyAutoSelect();
         }
 
         public void Deselect(int groupIndex, int itemIndex)
         {
             using var operation = new Operation(this);
             SelectWithGroupImpl(groupIndex, itemIndex, select: false);
-            ApplyAutoSelect();
         }
 
         public void DeselectAt(IndexPath index)
         {
             using var operation = new Operation(this);
             SelectWithPathImpl(index, select: false);
-            ApplyAutoSelect();
         }
 
         public bool IsSelected(int index) => _rootNode.IsSelected(index);
@@ -416,7 +420,7 @@ namespace Avalonia.Controls
             for (int i = 0; i < path.GetSize() - 1; i++)
             {
                 var childIndex = path.GetAt(i);
-                node = node.GetAt(childIndex, realizeChild: false);
+                node = node.GetAt(childIndex, false, default);
 
                 if (node == null)
                 {
@@ -451,7 +455,7 @@ namespace Avalonia.Controls
             }
 
             var isSelected = (bool?)false;
-            var childNode = _rootNode.GetAt(groupIndex, realizeChild: false);
+            var childNode = _rootNode.GetAt(groupIndex, false, default);
 
             if (childNode != null)
             {
@@ -470,7 +474,7 @@ namespace Avalonia.Controls
             for (int i = 0; i < path.GetSize() - 1; i++)
             {
                 var childIndex = path.GetAt(i);
-                node = node.GetAt(childIndex, realizeChild: false);
+                node = node.GetAt(childIndex, false, default);
 
                 if (node == null)
                 {
@@ -565,7 +569,6 @@ namespace Avalonia.Controls
         {
             using var operation = new Operation(this);
             ClearSelection(resetAnchor: true);
-            ApplyAutoSelect();
         }
 
         public IDisposable Update() => new Operation(this);
@@ -592,10 +595,13 @@ namespace Avalonia.Controls
             }
 
             OnSelectionChanged(e);
-            ApplyAutoSelect();
+            ApplyAutoSelect(true);
         }
 
-        internal IObservable<object?>? ResolvePath(object data, IndexPath dataIndexPath)
+        internal IObservable<object?>? ResolvePath(
+            object data,
+            IndexPath dataIndexPath,
+            IndexPath finalIndexPath)
         {
             IObservable<object?>? resolved = null;
 
@@ -604,18 +610,22 @@ namespace Avalonia.Controls
             {
                 if (_childrenRequestedEventArgs == null)
                 {
-                    _childrenRequestedEventArgs = new SelectionModelChildrenRequestedEventArgs(data, dataIndexPath, false);
+                    _childrenRequestedEventArgs = new SelectionModelChildrenRequestedEventArgs(
+                        data,
+                        dataIndexPath,
+                        finalIndexPath,
+                        false);
                 }
                 else
                 {
-                    _childrenRequestedEventArgs.Initialize(data, dataIndexPath, false);
+                    _childrenRequestedEventArgs.Initialize(data, dataIndexPath, finalIndexPath, false);
                 }
 
                 ChildrenRequested(this, _childrenRequestedEventArgs);
                 resolved = _childrenRequestedEventArgs.Children;
 
                 // Clear out the values in the args so that it cannot be used after the event handler call.
-                _childrenRequestedEventArgs.Initialize(null, default, true);
+                _childrenRequestedEventArgs.Initialize(null, default, default, true);
             }
 
             return resolved;
@@ -632,6 +642,8 @@ namespace Avalonia.Controls
             {
                 AnchorIndex = default;
             }
+
+            OnSelectionChanged();
         }
 
         private void OnSelectionChanged(SelectionModelSelectionChangedEventArgs? e = null)
@@ -667,6 +679,8 @@ namespace Avalonia.Controls
             {
                 AnchorIndex = new IndexPath(index);
             }
+
+            OnSelectionChanged();
         }
 
         private void SelectWithGroupImpl(int groupIndex, int itemIndex, bool select)
@@ -676,13 +690,15 @@ namespace Avalonia.Controls
                 ClearSelection(resetAnchor: true);
             }
 
-            var childNode = _rootNode.GetAt(groupIndex, realizeChild: true);
+            var childNode = _rootNode.GetAt(groupIndex, true, new IndexPath(groupIndex, itemIndex));
             var selected = childNode!.Select(itemIndex, select);
 
             if (selected)
             {
                 AnchorIndex = new IndexPath(groupIndex, itemIndex);
             }
+
+            OnSelectionChanged();
         }
 
         private void SelectWithPathImpl(IndexPath index, bool select)
@@ -711,6 +727,8 @@ namespace Avalonia.Controls
             {
                 AnchorIndex = index;
             }
+
+            OnSelectionChanged();
         }
 
         private void SelectRangeFromAnchorImpl(int index, bool select)
@@ -724,6 +742,7 @@ namespace Avalonia.Controls
             }
 
             _rootNode.SelectRange(new IndexRange(anchorIndex, index), select);
+            OnSelectionChanged();
         }
 
         private void SelectRangeFromAnchorWithGroupImpl(int endGroupIndex, int endItemIndex, bool select)
@@ -752,11 +771,13 @@ namespace Avalonia.Controls
 
             for (int groupIdx = startGroupIndex; groupIdx <= endGroupIndex; groupIdx++)
             {
-                var groupNode = _rootNode.GetAt(groupIdx, realizeChild: true)!;
+                var groupNode = _rootNode.GetAt(groupIdx, true, new IndexPath(endGroupIndex, endItemIndex))!;
                 int startIndex = groupIdx == startGroupIndex ? startItemIndex : 0;
                 int endIndex = groupIdx == endGroupIndex ? endItemIndex : groupNode.DataCount - 1;
                 groupNode.SelectRange(new IndexRange(startIndex, endIndex), select);
             }
+
+            OnSelectionChanged();
         }
 
         private void SelectRangeImpl(IndexPath start, IndexPath end, bool select)
@@ -784,6 +805,8 @@ namespace Avalonia.Controls
                         info.ParentNode!.Select(info.Path.GetAt(info.Path.GetSize() - 1), select);
                     }
                 });
+
+            OnSelectionChanged();
         }
 
         private void BeginOperation()
@@ -806,6 +829,8 @@ namespace Avalonia.Controls
 
             if (--_operationCount == 0)
             {
+                ApplyAutoSelect(false);
+
                 var changes = new List<SelectionNodeOperation>();
                 _rootNode.EndOperation(changes);
 
@@ -827,7 +852,7 @@ namespace Avalonia.Controls
             }
         }
 
-        private void ApplyAutoSelect()
+        private void ApplyAutoSelect(bool createOperation)
         {
             if (AutoSelect)
             {
@@ -835,8 +860,15 @@ namespace Avalonia.Controls
 
                 if (SelectedIndex == default && _rootNode.ItemsSourceView?.Count > 0)
                 {
-                    using var operation = new Operation(this);
-                    SelectImpl(0, true);
+                    if (createOperation)
+                    {
+                        using var operation = new Operation(this);
+                        SelectImpl(0, true);
+                    }
+                    else
+                    {
+                        SelectImpl(0, true);
+                    }
                 }
             }
         }

src/Avalonia.Controls/SelectionModelChangeSet.cs

@@ -135,7 +135,7 @@ namespace Avalonia.Controls
                 if (index >= currentIndex && index < currentIndex + currentCount)
                 {
                     int targetIndex = GetIndexAt(getRanges(info), index - currentIndex);
-                    item = info.Items?.GetAt(targetIndex);
+                    item = info.Items?.Count > targetIndex ? info.Items?.GetAt(targetIndex) : null;
                     break;
                 }
 

src/Avalonia.Controls/SelectionModelChildrenRequestedEventArgs.cs

@@ -16,15 +16,17 @@ namespace Avalonia.Controls
     {
         private object? _source;
         private IndexPath _sourceIndexPath;
+        private IndexPath _finalIndexPath;
         private bool _throwOnAccess;
         
         internal SelectionModelChildrenRequestedEventArgs(
             object source,
             IndexPath sourceIndexPath,
+            IndexPath finalIndexPath,
             bool throwOnAccess)
         {
             source = source ?? throw new ArgumentNullException(nameof(source));
-            Initialize(source, sourceIndexPath, throwOnAccess);
+            Initialize(source, sourceIndexPath, finalIndexPath, throwOnAccess);
         }
 
         /// <summary>
@@ -65,9 +67,26 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <summary>
+        /// Gets the index of the final object which is being attempted to be retrieved.
+        /// </summary>
+        public IndexPath FinalIndex
+        {
+            get
+            {
+                if (_throwOnAccess)
+                {
+                    throw new ObjectDisposedException(nameof(SelectionModelChildrenRequestedEventArgs));
+                }
+
+                return _finalIndexPath;
+            }
+        }
+
         internal void Initialize(
             object? source,
             IndexPath sourceIndexPath,
+            IndexPath finalIndexPath,
             bool throwOnAccess)
         {
             if (!throwOnAccess && source == null)
@@ -77,6 +96,7 @@ namespace Avalonia.Controls
 
             _source = source;
             _sourceIndexPath = sourceIndexPath;
+            _finalIndexPath = finalIndexPath;
             _throwOnAccess = throwOnAccess;
         }
     }

src/Avalonia.Controls/SelectionNode.cs

@@ -101,6 +101,7 @@ namespace Avalonia.Controls
 
                     ItemsSourceView = newDataSource;
 
+                    TrimInvalidSelections();
                     PopulateSelectedItemsFromSelectedIndices();
                     HookupCollectionChangedHandler();
                     OnSelectionChanged();
@@ -108,6 +109,26 @@ namespace Avalonia.Controls
             }
         }
 
+        private void TrimInvalidSelections()
+        {
+            if (_selected == null || ItemsSourceView == null)
+            {
+                return;
+            }
+
+            var validRange = ItemsSourceView.Count > 0 ? new IndexRange(0, ItemsSourceView.Count - 1) : new IndexRange(-1, -1);
+            var removed = new List<IndexRange>();
+            var removedCount = IndexRange.Intersect(_selected, validRange, removed);
+
+            if (removedCount > 0)
+            {
+                using var operation = _manager.Update();
+                SelectedCount -= removedCount;
+                OnSelectionChanged();
+                _operation!.Deselected(removed);
+            }
+        }
+
         public ItemsSourceView? ItemsSourceView { get; private set; }
         public int DataCount => ItemsSourceView?.Count ?? 0;
         public int ChildrenNodeCount => _childrenNodes.Count;
@@ -141,7 +162,7 @@ namespace Avalonia.Controls
         // create a bunch of leaf node instances - instead i use the same instance m_leafNode to avoid 
         // an explosion of node objects. However, I'm still creating the m_childrenNodes 
         // collection unfortunately.
-        public SelectionNode? GetAt(int index, bool realizeChild)
+        public SelectionNode? GetAt(int index, bool realizeChild, IndexPath finalIndexPath)
         {
             SelectionNode? child = null;
             
@@ -171,7 +192,7 @@ namespace Avalonia.Controls
                     if (childData != null)
                     {
                         var childDataIndexPath = IndexPath.CloneWithChildIndex(index);
-                        resolver = _manager.ResolvePath(childData, childDataIndexPath);
+                        resolver = _manager.ResolvePath(childData, childDataIndexPath, finalIndexPath);
                     }
 
                     if (resolver != null)
@@ -843,7 +864,7 @@ namespace Avalonia.Controls
                     int notSelectedCount = 0;
                     for (int i = 0; i < ChildrenNodeCount; i++)
                     {
-                        var child = GetAt(i, realizeChild: false);
+                        var child = GetAt(i, false, default);
 
                         if (child != null)
                         {

src/Avalonia.Controls/TreeView.cs

@@ -119,9 +119,10 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets or sets the selected item.
         /// </summary>
-        /// <summary>
-        /// Gets or sets the selected item.
-        /// </summary>
+        /// <remarks>
+        /// Note that setting this property only currently works if the item is expanded to be visible.
+        /// To select non-expanded nodes use `Selection.SelectedIndex`.
+        /// </remarks>
         public object SelectedItem
         {
             get => Selection.SelectedItem;
@@ -346,7 +347,7 @@ namespace Avalonia.Controls
 
                 if (container != null)
                 {
-                    container.BringIntoView();
+                    DispatcherTimer.RunOnce(container.BringIntoView, TimeSpan.Zero);
                 }
             }
         }
@@ -395,10 +396,17 @@ namespace Avalonia.Controls
 
         private void OnSelectionModelChildrenRequested(object sender, SelectionModelChildrenRequestedEventArgs e)
         {
-            var container = ItemContainerGenerator.Index.ContainerFromItem(e.Source) as ItemsControl;
+            var container = ItemContainerGenerator.Index.ContainerFromItem(e.Source) as TreeViewItem;
 
             if (container is object)
             {
+                if (e.SourceIndex.IsAncestorOf(e.FinalIndex))
+                {
+                    container.IsExpanded = true;
+                    container.ApplyTemplate();
+                    container.Presenter?.ApplyTemplate();
+                }
+
                 e.Children = Observable.CombineLatest(
                     container.GetObservable(TreeViewItem.IsExpandedProperty),
                     container.GetObservable(ItemsProperty),

src/Avalonia.Controls/Utils/SelectionTreeHelper.cs

@@ -28,7 +28,7 @@ namespace Avalonia.Controls.Utils
 
                 if (depth < path.GetSize() - 1)
                 {
-                    node = node.GetAt(childIndex, realizeChildren)!;
+                    node = node.GetAt(childIndex, realizeChildren, path)!;
                 }
             }
         }
@@ -50,7 +50,7 @@ namespace Avalonia.Controls.Utils
                 int count = realizeChildren ? nextNode.Node.DataCount : nextNode.Node.ChildrenNodeCount;
                 for (int i = count - 1; i >= 0; i--)
                 {
-                    var child = nextNode.Node.GetAt(i, realizeChildren);
+                    var child = nextNode.Node.GetAt(i, realizeChildren, nextNode.Path);
                     var childPath = nextNode.Path.CloneWithChildIndex(i);
                     if (child != null)
                     {
@@ -90,7 +90,7 @@ namespace Avalonia.Controls.Utils
 
                     for (int i = endIndex; i >= startIndex; i--)
                     {
-                        var child = node.GetAt(i, realizeChild: true);
+                        var child = node.GetAt(i, true, end);
                         if (child != null)
                         {
                             var childPath = currentPath.CloneWithChildIndex(i);
@@ -112,7 +112,7 @@ namespace Avalonia.Controls.Utils
                 int endIndex = depth < end.GetSize() && isEndPath ? end.GetAt(depth) : info.Node.DataCount - 1;
                 for (int i = endIndex; i >= startIndex; i--)
                 {
-                    var child = info.Node.GetAt(i, realizeChild: true);
+                    var child = info.Node.GetAt(i, true, end);
                     if (child != null)
                     {
                         var childPath = info.Path.CloneWithChildIndex(i);

src/Avalonia.Diagnostics/Diagnostics/ViewModels/MainViewModel.cs

@@ -2,6 +2,7 @@
 using Avalonia.Controls;
 using Avalonia.Diagnostics.Models;
 using Avalonia.Input;
+using Avalonia.Threading;
 
 namespace Avalonia.Diagnostics.ViewModels
 {
@@ -49,7 +50,21 @@ namespace Avalonia.Diagnostics.ViewModels
                     value is TreePageViewModel newTree &&
                     oldTree?.SelectedNode?.Visual is IControl control)
                 {
-                    newTree.SelectControl(control);
+                    // HACK: We want to select the currently selected control in the new tree, but
+                    // to select nested nodes in TreeView, currently the TreeView has to be able to
+                    // expand the parent nodes. Because at this point the TreeView isn't visible,
+                    // this will fail unless we schedule the selection to run after layout.
+                    DispatcherTimer.RunOnce(
+                        () =>
+                        {
+                            try
+                            {
+                                newTree.SelectControl(control);
+                            }
+                            catch { }
+                        },
+                        TimeSpan.FromMilliseconds(0),
+                        DispatcherPriority.ApplicationIdle);
                 }
 
                 RaiseAndSetIfChanged(ref _content, value);

src/Avalonia.Diagnostics/Diagnostics/ViewModels/TreeNode.cs

@@ -1,11 +1,11 @@
 using System;
+using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.Reactive;
 using System.Reactive.Linq;
 using Avalonia.Collections;
 using Avalonia.Controls;
 using Avalonia.LogicalTree;
-using Avalonia.Styling;
 using Avalonia.VisualTree;
 
 namespace Avalonia.Diagnostics.ViewModels
@@ -82,5 +82,41 @@ namespace Avalonia.Diagnostics.ViewModels
             get;
             private set;
         }
+
+        public IndexPath Index
+        {
+            get
+            {
+                var indices = new List<int>();
+                var child = this;
+                var parent = Parent;
+                
+                while (parent is object)
+                {
+                    indices.Add(IndexOf(parent.Children, child));
+                    child = child.Parent;
+                    parent = parent.Parent;
+                }
+
+                indices.Add(0);
+                indices.Reverse();
+                return new IndexPath(indices);
+            }
+        }
+
+        private static int IndexOf(IReadOnlyList<TreeNode> collection, TreeNode item)
+        {
+            var count = collection.Count;
+
+            for (var i = 0; i < count; ++i)
+            {
+                if (collection[i] == item)
+                {
+                    return i;
+                }
+            }
+
+            throw new AvaloniaInternalException("TreeNode was not present in parent Children collection.");
+        }
     }
 }

src/Avalonia.Diagnostics/Diagnostics/ViewModels/TreePageViewModel.cs

@@ -6,28 +6,40 @@ namespace Avalonia.Diagnostics.ViewModels
 {
     internal class TreePageViewModel : ViewModelBase, IDisposable
     {
-        private TreeNode _selected;
+        private TreeNode _selectedNode;
         private ControlDetailsViewModel _details;
         private string _propertyFilter;
 
         public TreePageViewModel(TreeNode[] nodes)
         {
             Nodes = nodes;
-        }
+            Selection = new SelectionModel
+            { 
+                SingleSelect = true,
+                Source = Nodes 
+            };
+
+            Selection.SelectionChanged += (s, e) =>
+            {
+                SelectedNode = (TreeNode)Selection.SelectedItem;
+            };
+       }
 
         public TreeNode[] Nodes { get; protected set; }
 
+        public SelectionModel Selection { get; }
+
         public TreeNode SelectedNode
         {
-            get => _selected;
-            set
+            get => _selectedNode;
+            private set
             {
                 if (Details != null)
                 {
                     _propertyFilter = Details.PropertyFilter;
                 }
 
-                if (RaiseAndSetIfChanged(ref _selected, value))
+                if (RaiseAndSetIfChanged(ref _selectedNode, value))
                 {
                     Details = value != null ?
                         new ControlDetailsViewModel(value.Visual, _propertyFilter) :
@@ -83,8 +95,8 @@ namespace Avalonia.Diagnostics.ViewModels
 
             if (node != null)
             {
-                SelectedNode = node;
                 ExpandNode(node.Parent);
+                Selection.SelectedIndex = node.Index;
             }
         }
 

src/Avalonia.Diagnostics/Diagnostics/Views/TreePageView.xaml

@@ -6,7 +6,7 @@
     <TreeView Name="tree"
               BorderThickness="0"
               Items="{Binding Nodes}"
-              SelectedItem="{Binding SelectedNode, Mode=TwoWay}">
+              Selection="{Binding Selection}">
       <TreeView.DataTemplates>
         <TreeDataTemplate DataType="vm:TreeNode"
                           ItemsSource="{Binding Children}">

tests/Avalonia.Controls.UnitTests/IndexRangeTests.cs

@@ -127,6 +127,88 @@ namespace Avalonia.Controls.UnitTests
             Assert.Empty(selected);
         }
 
+        [Fact]
+        public void Intersect_Should_Remove_Items_From_Beginning()
+        {
+            var ranges = new List<IndexRange> { new IndexRange(0, 10) };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(2, 12), removed);
+
+            Assert.Equal(2, result);
+            Assert.Equal(new[] { new IndexRange(2, 10) }, ranges);
+            Assert.Equal(new[] { new IndexRange(0, 1) }, removed);
+        }
+
+        [Fact]
+        public void Intersect_Should_Remove_Items_From_End()
+        {
+            var ranges = new List<IndexRange> { new IndexRange(0, 10) };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(0, 8), removed);
+
+            Assert.Equal(2, result);
+            Assert.Equal(new[] { new IndexRange(0, 8) }, ranges);
+            Assert.Equal(new[] { new IndexRange(9, 10) }, removed);
+        }
+
+        [Fact]
+        public void Intersect_Should_Remove_Entire_Range_Start()
+        {
+            var ranges = new List<IndexRange> { new IndexRange(0, 5), new IndexRange(6, 10) };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(6, 10), removed);
+
+            Assert.Equal(6, result);
+            Assert.Equal(new[] { new IndexRange(6, 10) }, ranges);
+            Assert.Equal(new[] { new IndexRange(0, 5) }, removed);
+        }
+
+        [Fact]
+        public void Intersect_Should_Remove_Entire_Range_End()
+        {
+            var ranges = new List<IndexRange> { new IndexRange(0, 5), new IndexRange(6, 10) };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(0, 4), removed);
+
+            Assert.Equal(6, result);
+            Assert.Equal(new[] { new IndexRange(0, 4) }, ranges);
+            Assert.Equal(new[] { new IndexRange(5, 10) }, removed);
+        }
+
+        [Fact]
+        public void Intersect_Should_Remove_Entire_Range_Start_End()
+        {
+            var ranges = new List<IndexRange> 
+            { 
+                new IndexRange(0, 2),
+                new IndexRange(3, 7), 
+                new IndexRange(8, 10) 
+            };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(3, 7), removed);
+
+            Assert.Equal(6, result);
+            Assert.Equal(new[] { new IndexRange(3, 7) }, ranges);
+            Assert.Equal(new[] { new IndexRange(0, 2), new IndexRange(8, 10) }, removed);
+        }
+
+        [Fact]
+        public void Intersect_Should_Remove_Entire_And_Partial_Range_Start_End()
+        {
+            var ranges = new List<IndexRange>
+            {
+                new IndexRange(0, 2),
+                new IndexRange(3, 7),
+                new IndexRange(8, 10)
+            };
+            var removed = new List<IndexRange>();
+            var result = IndexRange.Intersect(ranges, new IndexRange(4, 6), removed);
+
+            Assert.Equal(8, result);
+            Assert.Equal(new[] { new IndexRange(4, 6) }, ranges);
+            Assert.Equal(new[] { new IndexRange(0, 3), new IndexRange(7, 10) }, removed);
+        }
+
         [Fact]
         public void Remove_Should_Remove_Entire_Range()
         {

tests/Avalonia.Controls.UnitTests/SelectionModelTests.cs

@@ -1512,6 +1512,47 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(0, raised);
         }
 
+        [Fact]
+        public void Batch_Update_Selection_Is_Correct_Throughout()
+        {
+            var data = new[] { "foo", "bar", "baz", "qux" };
+            var target = new SelectionModel { Source = data };
+            var raised = 0;
+
+            using (target.Update())
+            {
+                target.Select(1);
+
+                Assert.Equal(new IndexPath(1), target.SelectedIndex);
+                Assert.Equal(new[] { new IndexPath(1) }, target.SelectedIndices);
+                Assert.Equal("bar", target.SelectedItem);
+                Assert.Equal(new[] { "bar" }, target.SelectedItems);
+
+                target.Deselect(1);
+
+                Assert.Equal(new IndexPath(), target.SelectedIndex);
+                Assert.Empty(target.SelectedIndices);
+                Assert.Null(target.SelectedItem);
+                Assert.Empty(target.SelectedItems);
+
+                target.SelectRange(new IndexPath(1), new IndexPath(1));
+
+                Assert.Equal(new IndexPath(1), target.SelectedIndex);
+                Assert.Equal(new[] { new IndexPath(1) }, target.SelectedIndices);
+                Assert.Equal("bar", target.SelectedItem);
+                Assert.Equal(new[] { "bar" }, target.SelectedItems);
+
+                target.ClearSelection();
+
+                Assert.Equal(new IndexPath(), target.SelectedIndex);
+                Assert.Empty(target.SelectedIndices);
+                Assert.Null(target.SelectedItem);
+                Assert.Empty(target.SelectedItems);
+            }
+
+            Assert.Equal(0, raised);
+        }
+
         [Fact]
         public void AutoSelect_Selects_When_Enabled()
         {
@@ -1713,6 +1754,30 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(0, raised);
         }
 
+        [Fact]
+        public void AutoSelect_Is_Applied_At_End_Of_Batch_Update()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { AutoSelect = true, Source = data };
+
+            using (target.Update())
+            {
+                target.ClearSelection();
+
+                Assert.Equal(new IndexPath(), target.SelectedIndex);
+                Assert.Empty(target.SelectedIndices);
+                Assert.Null(target.SelectedItem);
+                Assert.Empty(target.SelectedItems);
+            }
+
+            Assert.Equal(new IndexPath(0), target.SelectedIndex);
+            Assert.Equal(new[] { new IndexPath(0) }, target.SelectedIndices);
+            Assert.Equal("foo", target.SelectedItem);
+            Assert.Equal(new[] { "foo" }, target.SelectedItems);
+
+            Assert.Equal(new IndexPath(0), target.SelectedIndex);
+        }
+
         [Fact]
         public void Can_Replace_Parent_Children_Collection()
         {
@@ -1806,6 +1871,87 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(0, node.PropertyChangedSubscriptions);
         }
 
+        [Fact]
+        public void Setting_SelectedIndex_To_Minus_1_Clears_Selection()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { Source = data };
+            target.SelectedIndex = new IndexPath(1);
+            target.SelectedIndex = new IndexPath(-1);
+            Assert.Empty(target.SelectedIndices);
+        }
+
+        [Fact]
+        public void Assigning_Source_With_Less_Items_Than_Previous_Clears_Selection()
+        {
+            var data = new[] { "foo", "bar", "baz", "boo", "hoo" };
+            var smallerData = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { RetainSelectionOnReset = true };
+            target.Source = data;
+            target.SelectedIndex = new IndexPath(4);
+            target.Source = smallerData;
+            Assert.Empty(target.SelectedIndices);
+        }
+
+        [Fact]
+        public void Initializing_Source_With_Less_Items_Than_Selection_Trims_Selection()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel();
+            target.SelectedIndex = new IndexPath(4);
+            target.Source = data;
+            Assert.Empty(target.SelectedIndices);
+        }
+
+        [Fact]
+        public void Initializing_Source_With_Less_Items_Than_Selection_Trims_Selection_RetainSelection()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { RetainSelectionOnReset = true };
+            target.SelectedIndex = new IndexPath(4);
+            target.Source = data;
+            Assert.Empty(target.SelectedIndices);
+        }
+
+        [Fact]
+        public void Initializing_Source_With_Less_Items_Than_Multiple_Selection_Trims_Selection()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { RetainSelectionOnReset = true };
+            target.Select(4);
+            target.Select(2);
+            target.Source = data;
+            Assert.Equal(1, target.SelectedIndices.Count);
+            Assert.Equal(new IndexPath(2), target.SelectedIndices.First());
+        }
+
+        [Fact]
+        public void Initializing_Source_With_Less_Items_Than_Selection_Raises_SelectionChanged()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel();
+            var raised = 0;
+
+            target.SelectedIndex = new IndexPath(4);
+
+            target.SelectionChanged += (s, e) =>
+            {
+                if (raised == 0)
+                {
+                    Assert.Equal(new[] { Path(4) }, e.DeselectedIndices);
+                    Assert.Equal(new object[] { null }, e.DeselectedItems);
+                    Assert.Empty(e.SelectedIndices);
+                    Assert.Empty(e.SelectedItems);
+                }
+
+                ++raised;
+            };
+
+            target.Source = data;
+            
+            Assert.Equal(2, raised);
+        }
+
         private int GetSubscriberCount(AvaloniaList<object> list)
         {
             return ((INotifyCollectionChangedDebug)list).GetCollectionChangedSubscribers()?.Length ?? 0;

tests/Avalonia.Controls.UnitTests/TabControlTests.cs

@@ -1,10 +1,12 @@
 using System;
+using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
 using Avalonia.Collections;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
+using Avalonia.Controls.Utils;
 using Avalonia.LogicalTree;
 using Avalonia.Styling;
 using Avalonia.UnitTests;
@@ -325,6 +327,28 @@ namespace Avalonia.Controls.UnitTests
             Assert.NotEqual(dataContext, tabItem.Content);
         }
 
+        [Fact]
+        public void Can_Have_Empty_Tab_Control()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <TabControl Name='tabs' Items='{Binding Tabs}'/>
+</Window>";
+                var loader = new Markup.Xaml.AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var tabControl = window.FindControl<TabControl>("tabs");
+
+                tabControl.DataContext = new { Tabs = new List<string>() };
+                window.ApplyTemplate();
+
+                Assert.Equal(0, tabControl.Items.Count());
+            }
+        }
+
         private IControlTemplate TabControlTemplate()
         {
             return new FuncControlTemplate<TabControl>((parent, scope) =>

tests/Avalonia.Controls.UnitTests/TreeViewTests.cs

@@ -118,313 +118,340 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Clicking_Item_Should_Select_It()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var item = tree[0].Children[1].Children[0];
-            var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
+                var item = tree[0].Children[1].Children[0];
+                var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
 
-            Assert.NotNull(container);
+                Assert.NotNull(container);
 
-            _mouse.Click(container);
+                _mouse.Click(container);
 
-            Assert.Equal(item, target.SelectedItem);
-            Assert.True(container.IsSelected);
+                Assert.Equal(item, target.SelectedItem);
+                Assert.True(container.IsSelected);
+            }
         }
 
         [Fact]
         public void Clicking_WithControlModifier_Selected_Item_Should_Deselect_It()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var item = tree[0].Children[1].Children[0];
-            var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
+                var item = tree[0].Children[1].Children[0];
+                var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
 
-            Assert.NotNull(container);
+                Assert.NotNull(container);
 
-            target.SelectedItem = item;
+                target.SelectedItem = item;
 
-            Assert.True(container.IsSelected);
+                Assert.True(container.IsSelected);
 
-            _mouse.Click(container, modifiers: KeyModifiers.Control);
+                _mouse.Click(container, modifiers: KeyModifiers.Control);
 
-            Assert.Null(target.SelectedItem);
-            Assert.False(container.IsSelected);
+                Assert.Null(target.SelectedItem);
+                Assert.False(container.IsSelected);
+            }
         }
 
         [Fact]
         public void Clicking_WithControlModifier_Not_Selected_Item_Should_Select_It()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var item1 = tree[0].Children[1].Children[0];
-            var container1 = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item1);
+                var item1 = tree[0].Children[1].Children[0];
+                var container1 = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item1);
 
-            var item2 = tree[0].Children[1];
-            var container2 = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item2);
+                var item2 = tree[0].Children[1];
+                var container2 = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item2);
 
-            Assert.NotNull(container1);
-            Assert.NotNull(container2);
+                Assert.NotNull(container1);
+                Assert.NotNull(container2);
 
-            target.SelectedItem = item1;
+                target.SelectedItem = item1;
 
-            Assert.True(container1.IsSelected);
+                Assert.True(container1.IsSelected);
 
-            _mouse.Click(container2, modifiers: KeyModifiers.Control);
-            
-            Assert.Equal(item2, target.SelectedItem);
-            Assert.False(container1.IsSelected);
-            Assert.True(container2.IsSelected);
+                _mouse.Click(container2, modifiers: KeyModifiers.Control);
+
+                Assert.Equal(item2, target.SelectedItem);
+                Assert.False(container1.IsSelected);
+                Assert.True(container2.IsSelected);
+            }
         }
 
         [Fact]
         public void Clicking_WithControlModifier_Selected_Item_Should_Deselect_And_Remove_From_SelectedItems()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var rootNode = tree[0];
+                var rootNode = tree[0];
 
-            var item1 = rootNode.Children[0];
-            var item2 = rootNode.Children.Last();
+                var item1 = rootNode.Children[0];
+                var item2 = rootNode.Children.Last();
 
-            var item1Container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item1);
-            var item2Container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item2);
+                var item1Container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item1);
+                var item2Container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item2);
 
-            ClickContainer(item1Container, KeyModifiers.Control);
-            Assert.True(item1Container.IsSelected);
+                ClickContainer(item1Container, KeyModifiers.Control);
+                Assert.True(item1Container.IsSelected);
 
-            ClickContainer(item2Container, KeyModifiers.Control);
-            Assert.True(item2Container.IsSelected);
+                ClickContainer(item2Container, KeyModifiers.Control);
+                Assert.True(item2Container.IsSelected);
 
-            Assert.Equal(new[] {item1, item2}, target.Selection.SelectedItems.OfType<Node>());
+                Assert.Equal(new[] { item1, item2 }, target.Selection.SelectedItems.OfType<Node>());
 
-            ClickContainer(item1Container, KeyModifiers.Control);
-            Assert.False(item1Container.IsSelected);
+                ClickContainer(item1Container, KeyModifiers.Control);
+                Assert.False(item1Container.IsSelected);
 
-            Assert.DoesNotContain(item1, target.Selection.SelectedItems.OfType<Node>());
+                Assert.DoesNotContain(item1, target.Selection.SelectedItems.OfType<Node>());
+            }
         }
 
         [Fact]
         public void Clicking_WithShiftModifier_DownDirection_Should_Select_Range_Of_Items()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var rootNode = tree[0];
+                var rootNode = tree[0];
 
-            var from = rootNode.Children[0];
-            var to = rootNode.Children.Last();
+                var from = rootNode.Children[0];
+                var to = rootNode.Children.Last();
 
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
 
-            ClickContainer(fromContainer, KeyModifiers.None);
+                ClickContainer(fromContainer, KeyModifiers.None);
 
-            Assert.True(fromContainer.IsSelected);
+                Assert.True(fromContainer.IsSelected);
 
-            ClickContainer(toContainer, KeyModifiers.Shift);
-            AssertChildrenSelected(target, rootNode);
+                ClickContainer(toContainer, KeyModifiers.Shift);
+                AssertChildrenSelected(target, rootNode);
+            }
         }
 
         [Fact]
         public void Clicking_WithShiftModifier_UpDirection_Should_Select_Range_Of_Items()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var rootNode = tree[0];
+                var rootNode = tree[0];
 
-            var from = rootNode.Children.Last();
-            var to = rootNode.Children[0];
+                var from = rootNode.Children.Last();
+                var to = rootNode.Children[0];
 
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
 
-            ClickContainer(fromContainer, KeyModifiers.None);
+                ClickContainer(fromContainer, KeyModifiers.None);
 
-            Assert.True(fromContainer.IsSelected);
+                Assert.True(fromContainer.IsSelected);
 
-            ClickContainer(toContainer, KeyModifiers.Shift);
-            AssertChildrenSelected(target, rootNode);
+                ClickContainer(toContainer, KeyModifiers.Shift);
+                AssertChildrenSelected(target, rootNode);
+            }
         }
 
         [Fact]
         public void Clicking_First_Item_Of_SelectedItems_Should_Select_Only_It()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var rootNode = tree[0];
+                var rootNode = tree[0];
 
-            var from = rootNode.Children.Last();
-            var to = rootNode.Children[0];
+                var from = rootNode.Children.Last();
+                var to = rootNode.Children[0];
 
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
 
-            ClickContainer(fromContainer, KeyModifiers.None);
+                ClickContainer(fromContainer, KeyModifiers.None);
 
-            ClickContainer(toContainer, KeyModifiers.Shift);
-            AssertChildrenSelected(target, rootNode);
+                ClickContainer(toContainer, KeyModifiers.Shift);
+                AssertChildrenSelected(target, rootNode);
 
-            ClickContainer(fromContainer, KeyModifiers.None);
+                ClickContainer(fromContainer, KeyModifiers.None);
 
-            Assert.True(fromContainer.IsSelected);
+                Assert.True(fromContainer.IsSelected);
 
-            foreach (var child in rootNode.Children)
-            {
-                if (child == from)
+                foreach (var child in rootNode.Children)
                 {
-                    continue;
-                }
+                    if (child == from)
+                    {
+                        continue;
+                    }
 
-                var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(child);
+                    var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(child);
 
-                Assert.False(container.IsSelected);
+                    Assert.False(container.IsSelected);
+                }
             }
         }
 
         [Fact]
         public void Setting_SelectedItem_Should_Set_Container_Selected()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var item = tree[0].Children[1].Children[0];
-            var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
+                var item = tree[0].Children[1].Children[0];
+                var container = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(item);
 
-            Assert.NotNull(container);
+                Assert.NotNull(container);
 
-            target.SelectedItem = item;
+                target.SelectedItem = item;
 
-            Assert.True(container.IsSelected);
+                Assert.True(container.IsSelected);
+            }
         }
 
         [Fact]
         public void Setting_SelectedItem_Should_Raise_SelectedItemChanged_Event()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            ExpandAll(target);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                ExpandAll(target);
 
-            var item = tree[0].Children[1].Children[0];
+                var item = tree[0].Children[1].Children[0];
 
-            var called = false;
-            target.SelectionChanged += (s, e) =>
-            {
-                Assert.Empty(e.RemovedItems);
-                Assert.Equal(1, e.AddedItems.Count);
-                Assert.Same(item, e.AddedItems[0]);
-                called = true;
-            };
+                var called = false;
+                target.SelectionChanged += (s, e) =>
+                {
+                    Assert.Empty(e.RemovedItems);
+                    Assert.Equal(1, e.AddedItems.Count);
+                    Assert.Same(item, e.AddedItems[0]);
+                    called = true;
+                };
 
-            target.SelectedItem = item;
-            Assert.True(called);
+                target.SelectedItem = item;
+                Assert.True(called);
+            }
         }
 
         [Fact]
@@ -564,7 +591,7 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Keyboard_Navigation_Should_Move_To_Last_Selected_Node()
         {
-            using (UnitTestApplication.Start(TestServices.RealFocus))
+            using (Application())
             {
                 var focus = FocusManager.Instance;
                 var navigation = AvaloniaLocator.Current.GetService<IKeyboardNavigationHandler>();
@@ -647,7 +674,7 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Pressing_SelectAll_Gesture_With_Downward_Range_Selected_Should_Select_All_Nodes()
         {
-            using (UnitTestApplication.Start())
+            using (Application())
             {
                 var tree = CreateTestTreeData();
                 var target = new TreeView
@@ -694,7 +721,7 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Pressing_SelectAll_Gesture_With_Upward_Range_Selected_Should_Select_All_Nodes()
         {
-            using (UnitTestApplication.Start())
+            using (Application())
             {
                 var tree = CreateTestTreeData();
                 var target = new TreeView
@@ -768,97 +795,106 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Right_Click_On_UnselectedItem_Should_Clear_Existing_Selection()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
 
-            var rootNode = tree[0];
-            var to = rootNode.Children[0];
-            var then = rootNode.Children[1];
+                var rootNode = tree[0];
+                var to = rootNode.Children[0];
+                var then = rootNode.Children[1];
 
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(rootNode);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
-            var thenContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(then);
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(rootNode);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var thenContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(then);
 
-            ClickContainer(fromContainer, KeyModifiers.None);
-            ClickContainer(toContainer, KeyModifiers.Shift);
+                ClickContainer(fromContainer, KeyModifiers.None);
+                ClickContainer(toContainer, KeyModifiers.Shift);
 
-            Assert.Equal(2, target.Selection.SelectedItems.Count);
+                Assert.Equal(2, target.Selection.SelectedItems.Count);
 
-            _mouse.Click(thenContainer, MouseButton.Right);
+                _mouse.Click(thenContainer, MouseButton.Right);
 
-            Assert.Equal(1, target.Selection.SelectedItems.Count);
+                Assert.Equal(1, target.Selection.SelectedItems.Count);
+            }
         }
 
         [Fact]
         public void Shift_Right_Click_Should_Not_Select_Multiple()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
 
-            var rootNode = tree[0];
-            var from = rootNode.Children[0];
-            var to = rootNode.Children[1];
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var rootNode = tree[0];
+                var from = rootNode.Children[0];
+                var to = rootNode.Children[1];
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
 
-            _mouse.Click(fromContainer);
-            _mouse.Click(toContainer, MouseButton.Right, modifiers: KeyModifiers.Shift);
+                _mouse.Click(fromContainer);
+                _mouse.Click(toContainer, MouseButton.Right, modifiers: KeyModifiers.Shift);
 
-            Assert.Equal(1, target.Selection.SelectedItems.Count);
+                Assert.Equal(1, target.Selection.SelectedItems.Count);
+            }
         }
 
         [Fact]
         public void Ctrl_Right_Click_Should_Not_Select_Multiple()
         {
-            var tree = CreateTestTreeData();
-            var target = new TreeView
+            using (Application())
             {
-                Template = CreateTreeViewTemplate(),
-                Items = tree,
-                SelectionMode = SelectionMode.Multiple,
-            };
+                var tree = CreateTestTreeData();
+                var target = new TreeView
+                {
+                    Template = CreateTreeViewTemplate(),
+                    Items = tree,
+                    SelectionMode = SelectionMode.Multiple,
+                };
 
-            var visualRoot = new TestRoot();
-            visualRoot.Child = target;
+                var visualRoot = new TestRoot();
+                visualRoot.Child = target;
 
-            CreateNodeDataTemplate(target);
-            ApplyTemplates(target);
-            target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
+                CreateNodeDataTemplate(target);
+                ApplyTemplates(target);
+                target.ExpandSubTree((TreeViewItem)target.Presenter.Panel.Children[0]);
 
-            var rootNode = tree[0];
-            var from = rootNode.Children[0];
-            var to = rootNode.Children[1];
-            var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
-            var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
+                var rootNode = tree[0];
+                var from = rootNode.Children[0];
+                var to = rootNode.Children[1];
+                var fromContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(from);
+                var toContainer = (TreeViewItem)target.ItemContainerGenerator.Index.ContainerFromItem(to);
 
-            _mouse.Click(fromContainer);
-            _mouse.Click(toContainer, MouseButton.Right, modifiers: KeyModifiers.Control);
+                _mouse.Click(fromContainer);
+                _mouse.Click(toContainer, MouseButton.Right, modifiers: KeyModifiers.Control);
 
-            Assert.Equal(1, target.Selection.SelectedItems.Count);
+                Assert.Equal(1, target.Selection.SelectedItems.Count);
+            }
         }
 
         [Fact]
@@ -944,7 +980,7 @@ namespace Avalonia.Controls.UnitTests
         public void Auto_Expanding_In_Style_Should_Not_Break_Range_Selection()
         {
             /// Issue #2980.
-            using (UnitTestApplication.Start(TestServices.RealStyler))
+            using (Application())
             {
                 var target = new DerivedTreeView
                 {
@@ -1183,12 +1219,12 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
-        void ClickContainer(IControl container, KeyModifiers modifiers)
+        private void ClickContainer(IControl container, KeyModifiers modifiers)
         {
             _mouse.Click(container, modifiers: modifiers);
         }
 
-        void AssertChildrenSelected(TreeView treeView, Node rootNode)
+        private void AssertChildrenSelected(TreeView treeView, Node rootNode)
         {
             foreach (var child in rootNode.Children)
             {
@@ -1198,6 +1234,16 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        private IDisposable Application()
+        {
+            return UnitTestApplication.Start(
+                TestServices.MockThreadingInterface.With(
+                    focusManager: new FocusManager(),
+                    keyboardDevice: () => new KeyboardDevice(),
+                    keyboardNavigation: new KeyboardNavigationHandler(),
+                    inputManager: new InputManager()));
+        }
+
         private class Node : NotifyingBase
         {
             private IAvaloniaList<Node> _children;