private void CreateIndicatorRect(CanvasControl canvasControl)
        {
            if (canvasObject != null)
            {
                canvasObject.Remove();
            }
            // visualize it
            var shapePaintable = new RectangleIndicatorInstaller(targetBounds)
            {
                Template = (DataTemplate)canvasControl.TryFindResource("LayerPaintableRectangleTemplateKey")
            };

            canvasObject = shapePaintable.AddCanvasObject(canvasControl.CanvasContext, ((GraphControl)canvasControl).BackgroundGroup, targetBounds);
        }