Removes markup for empty implicit collections.

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

@@ -358,8 +358,6 @@ namespace ICSharpCode.WpfDesign.Tests.Designer
 			Assert.IsTrue(((System.Windows.Input.InputBindingCollection)inputbinding.ValueOnInstance).Count == inputbinding.CollectionElements.Count);
 			
 			const string undoXaml = @"<TextBlock>
-  <TextBlock.InputBindings>
-  </TextBlock.InputBindings>
 </TextBlock>";
 			
 			s.Undo();

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.XamlDom/Project/CollectionElementsCollection.cs

@@ -61,6 +61,11 @@ namespace ICSharpCode.WpfDesign.XamlDom
 			this[index].RemoveNodeFromParent();
 			this[index].ParentProperty = null;
 			base.RemoveItem(index);
+			
+			// If item was removed from an implicit collection that is now empty we reset its property to remove markup for the property if still there.
+			if (Count == 0 && property.PropertyValue == null) {
+				property.Reset();
+			}
 		}
 		
 		protected override void InsertItem(int index, XamlPropertyValue item)