Added tests for different combinations of Remove, Clear and Reset with multiple undo/redo operations on collections. Added ResetAction to make the tests pass.

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Xaml/XamlModelCollectionElementsCollection.cs

@@ -164,6 +164,11 @@ namespace ICSharpCode.WpfDesign.Designer.Xaml
 			Execute(new RemoveAtAction(this, index, (XamlDesignItem)this[index]));
 		}
 		
+		internal ITransactionItem CreateResetTransaction()
+		{
+			return new ResetAction(this);
+		}
+		
 		void Execute(ITransactionItem item)
 		{
 			UndoService undoService = context.Services.GetService<UndoService>();
@@ -279,5 +284,60 @@ namespace ICSharpCode.WpfDesign.Designer.Xaml
 				return false;
 			}
 		}
+		
+		sealed class ResetAction : ITransactionItem
+		{
+			readonly XamlModelCollectionElementsCollection collection;
+			readonly XamlDesignItem[] items;
+			
+			public ResetAction(XamlModelCollectionElementsCollection collection)
+			{
+				this.collection = collection;
+				
+				items = new XamlDesignItem[collection.Count];
+				for (int i = 0; i < collection.Count; i++) {
+					items[i] = (XamlDesignItem)collection[i];
+				}
+			}
+			
+			#region ITransactionItem implementation
+			
+			public void Do()
+			{
+				for (int i = items.Length - 1; i >= 0; i--) {
+					collection.RemoveInternal(i, items[i]);
+				}
+				collection.modelProperty.XamlDesignItem.NotifyPropertyChanged(collection.modelProperty);
+			}
+			public void Undo()
+			{
+				for (int i = 0; i < items.Length; i++) {
+					collection.InsertInternal(i, items[i]);
+				}
+				collection.modelProperty.XamlDesignItem.NotifyPropertyChanged(collection.modelProperty);
+			}
+			public bool MergeWith(ITransactionItem other)
+			{
+				return false;
+			}
+			
+			#endregion
+			
+			#region IUndoAction implementation
+			
+			public ICollection<DesignItem> AffectedElements {
+				get {
+					return new DesignItem[] { collection.modelProperty.DesignItem };
+				}
+			}
+			
+			public string Title {
+				get {
+					return "Reset collection";
+				}
+			}
+			
+			#endregion
+		}
 	}
 }

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Xaml/XamlModelProperty.cs

@@ -249,11 +249,12 @@ namespace ICSharpCode.WpfDesign.Designer.Xaml
 		
 		public sealed class PropertyChangeAction : ITransactionItem
 		{
-			XamlModelProperty property;
-			XamlPropertyValue oldValue;
+			readonly XamlModelProperty property;
+			readonly XamlPropertyValue oldValue;
 			XamlPropertyValue newValue;
-			bool oldIsSet;
+			readonly bool oldIsSet;
 			bool newIsSet;
+			readonly ITransactionItem collectionTransactionItem;
 			
 			public PropertyChangeAction(XamlModelProperty property, XamlPropertyValue newValue, bool newIsSet)
 			{
@@ -263,6 +264,10 @@ namespace ICSharpCode.WpfDesign.Designer.Xaml
 				
 				oldIsSet = property._property.IsSet;
 				oldValue = property._property.PropertyValue;
+				
+				if (oldIsSet && oldValue == null && property.IsCollection) {
+					collectionTransactionItem = property._collectionElements.CreateResetTransaction();
+				}
 			}
 			
 			public string Title {
@@ -276,6 +281,10 @@ namespace ICSharpCode.WpfDesign.Designer.Xaml
 			
 			public void Do()
 			{
+				if (collectionTransactionItem != null) {
+					collectionTransactionItem.Do();
+				}
+				
 				if (newIsSet)
 					property.SetValueInternal(newValue);
 				else
@@ -284,8 +293,13 @@ namespace ICSharpCode.WpfDesign.Designer.Xaml
 			
 			public void Undo()
 			{
-				if (oldIsSet)
-					property.SetValueInternal(oldValue);
+				if (oldIsSet) {
+					if (collectionTransactionItem != null) {
+						collectionTransactionItem.Undo();
+					} else {
+						property.SetValueInternal(oldValue);
+					}
+				}
 				else
 					property.ResetInternal();
 			}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Tests/Designer/ModelTests.cs

@@ -377,8 +377,7 @@ namespace ICSharpCode.WpfDesign.Tests.Designer
 			AssertLog("");
 		}
 		
-		[Test]
-		public void UndoRedoRemoveClearResetInputBindings()
+		void UndoRedoInputBindingsRemoveClearResetInternal(bool remove, bool clear, bool reset)
 		{
 			const string originalXaml =  "<TextBlock Text=\"My text\" />";
 			
@@ -420,9 +419,12 @@ namespace ICSharpCode.WpfDesign.Tests.Designer
 				DesignItem di = inputbinding.CollectionElements.First();
 				
 				// Remove, Clear, Reset combination caused exception at first Undo after this group commit before the issue was fixed
-				inputbinding.CollectionElements.Remove(di);
-				inputbinding.CollectionElements.Clear();
-				inputbinding.Reset();
+				if (remove)
+					inputbinding.CollectionElements.Remove(di);
+				if (clear)
+					inputbinding.CollectionElements.Clear();
+				if (reset)
+					inputbinding.Reset();
 				
 				di = component.RegisterComponentForDesigner(new System.Windows.Input.MouseBinding());
 				di.Properties["Gesture"].SetValue(System.Windows.Input.MouseAction.LeftDoubleClick);
@@ -452,6 +454,48 @@ namespace ICSharpCode.WpfDesign.Tests.Designer
 			AssertLog("");
 		}
 		
+		[Test]
+		public void UndoRedoInputBindingsRemoveClearReset()
+		{
+			UndoRedoInputBindingsRemoveClearResetInternal(true, true, true);
+		}
+		
+		[Test]
+		public void UndoRedoInputBindingsRemove()
+		{
+			UndoRedoInputBindingsRemoveClearResetInternal(true, false, false);
+		}
+		
+		[Test]
+		public void UndoRedoInputBindingsClear()
+		{
+			UndoRedoInputBindingsRemoveClearResetInternal(false, true, false);
+		}
+		
+		[Test]
+		public void UndoRedoInputBindingsReset()
+		{
+			UndoRedoInputBindingsRemoveClearResetInternal(false, false, true);
+		}
+		
+		[Test]
+		public void UndoRedoInputBindingsRemoveClear()
+		{
+			UndoRedoInputBindingsRemoveClearResetInternal(true, true, false);
+		}
+		
+		[Test]
+		public void UndoRedoInputBindingsRemoveReset()
+		{
+			UndoRedoInputBindingsRemoveClearResetInternal(true, false, true);
+		}
+		
+		[Test]
+		public void UndoRedoInputBindingsClearReset()
+		{
+			UndoRedoInputBindingsRemoveClearResetInternal(false, true, true);
+		}
+		
 		[Test]
 		public void AddTextBoxToCanvas()
 		{