/// <summary>
        /// Dragging has ended, see if VM is IDiagramDesignerItem and notify of resizing end.
        /// </summary>
        void ResizeThumb_DragCompleted(object sender, DragCompletedEventArgs e)
        {
            if (!dragStarted)
            {
                return;
            }
            else
            {
                dragStarted = false;
            }

            DiagramItemsResizeInfo resizeInfo = diagramDesignerVM.CalcResizeInfo(this.selectedItemsVM, e.HorizontalChange, e.VerticalChange, direction.Value);

            diagramDesignerVM.ResizeElements(this.selectedItemsVM, resizeInfo);

            // remove drag adorner
            if (this.IsMouseCaptured)
            {
                this.ReleaseMouseCapture();
            }

            AdornerLayer adornerLayer = AdornerLayer.GetAdornerLayer(this.diagramDesigner);

            if (adornerLayer != null)
            {
                adornerLayer.Remove(this.dragAdorner);
            }

            e.Handled = false;
        }