Hot-fixed memory leak caused by Canvas.Children.Clear() not releasing instances properly.

src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/Drawing/GraphDrawer.cs

@@ -26,6 +26,7 @@ namespace Debugger.AddIn.Visualizers.Graph
 	{
 		Canvas canvas;
 		TextBlock edgeTooltip = new TextBlock();
+		static double animationDurationSeconds = 0.5;
 		
 		public GraphDrawer(Canvas canvas)
 		{
@@ -50,8 +51,7 @@ namespace Debugger.AddIn.Visualizers.Graph
 				return;
 			}
 			
-			double seconds = 0.5;
-			var durationMove = new Duration(TimeSpan.FromSeconds(seconds));
+			var durationMove = new Duration(TimeSpan.FromSeconds(animationDurationSeconds));
 			var durationFade = durationMove;
 			
 			DoubleAnimation fadeOutAnim = new DoubleAnimation(1.0, 0.0, durationFade);
@@ -82,7 +82,14 @@ namespace Debugger.AddIn.Visualizers.Graph
 				
 				PointAnimation anim = new PointAnimation();
 				if (first) {
-					anim.Completed += new EventHandler((o, e) => { Draw(newGraph); });
+					anim.Completed += (o, e) => {
+						Draw(newGraph);
+						if (oldGraph != null) {
+							foreach (var oldNode in oldGraph.Nodes) {
+								oldNode.ReleaseNodeVisualControl();
+							}
+						}
+					};
 					first = false;
 				}
 				anim.From = node.LeftTop;

src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/Drawing/PositionedGraphNodeControl.xaml.cs

@@ -59,6 +59,11 @@ namespace Debugger.AddIn.Visualizers.Graph.Drawing
 		/// <param name="node"></param>
 		public void SetDataContext(PositionedNode node)
 		{
+			if (node == null) {
+				this.DataContext = null;
+				this.listView.ItemsSource = null;
+				return;
+			}
 			this.DataContext = node;
 			this.Root = node.Content;
 			this.items = GetInitialItems(this.Root);
@@ -97,25 +102,19 @@ namespace Debugger.AddIn.Visualizers.Graph.Drawing
 		void PropertyExpandButton_Click(object sender, RoutedEventArgs e)
 		{
 			var clickedButton = (ToggleButton)e.Source;
-			ContentPropertyNode clickedNode = null;
-			try
-			{
-				clickedNode = (ContentPropertyNode)(clickedButton).DataContext;
-			}
-			catch(InvalidCastException)
-			{
-				throw new InvalidOperationException("Clicked property expand button, button shouln't be there - DataContext is not PropertyNodeViewModel.");
+			if (clickedButton.DataContext == null) return;
+			ContentPropertyNode clickedNode = clickedButton.DataContext as ContentPropertyNode;
+			clickedNode = clickedButton.DataContext as ContentPropertyNode;
+			if (clickedNode == null) {
+				throw new InvalidOperationException("Clicked property expand button, button shouln't be there - DataContext is not ContentPropertyNode.");
 			}
 			
 			PositionedNodeProperty property = clickedNode.Property;
-			clickedButton.Content = property.IsPropertyExpanded ? "-" : "+";
+			clickedButton.Content = property.IsPropertyExpanded ? "-" : "+";	// could be done with a converter
 			
-			if (property.IsPropertyExpanded)
-			{
+			if (property.IsPropertyExpanded) {
 				OnPropertyExpanded(property);
-			}
-			else
-			{
+			} else {
 				OnPropertyCollapsed(property);
 			}
 		}
@@ -123,7 +122,8 @@ namespace Debugger.AddIn.Visualizers.Graph.Drawing
 		void NestedExpandButton_Click(object sender, RoutedEventArgs e)
 		{
 			var clickedButton = (ToggleButton)e.Source;
-			var clickedNode = (ContentNode)(clickedButton).DataContext;
+			var clickedNode = clickedButton.DataContext as ContentNode;
+			if (clickedNode == null) return;
 			int clickedIndex = this.items.IndexOf(clickedNode);
 			clickedButton.Content = clickedNode.IsExpanded ? "-" : "+";	// could be done by a converter
 
@@ -199,8 +199,10 @@ namespace Debugger.AddIn.Visualizers.Graph.Drawing
 		
 		void SetEdgeStrokeThickness(ListViewItem listViewItem, int thickness)
 		{
-			var clickedNode = (ContentNode)listViewItem.DataContext;
-			var propNode = clickedNode as ContentPropertyNode;
+			var propNode = listViewItem.DataContext as ContentPropertyNode;
+			if (propNode == null) {
+				return;
+			}
 			if (propNode != null && propNode.Property != null && propNode.Property.Edge != null && propNode.Property.Edge.Spline != null) {
 				propNode.Property.Edge.Spline.StrokeThickness = thickness;
 			}

src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/Layout/PositionedNode.cs

@@ -56,6 +56,12 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 		/// </summary>
 		public PositionedGraphNodeControl NodeVisualControl { get; private set; }
 		
+		public void ReleaseNodeVisualControl()
+		{
+			this.NodeVisualControl.SetDataContext(null);
+			this.NodeVisualControl = null;
+		}
+		
 		void InitContentFromObjectNode(Expanded expanded)
 		{
 			this.Content = new ContentNode(this, null);

src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ObjectGraphControl.xaml.cs

@@ -62,8 +62,6 @@ namespace Debugger.AddIn.Visualizers.Graph
 		
 		public void Refresh()
 		{
-			Log.Info("Object graph - refresh");
-			GC.Collect();
 			// Almost all of the blocking is done ContentPropertyNode.Evaluate,
 			// which is being called by WPF for all the properties.
 			// It would be better if we were filling the node texts ourselves in a loop,