void DiagramElement_Loaded(object sender, RoutedEventArgs e)
 {
     if (base.Template != null)
     {
         ContentPresenter contentPresenter =
             this.Template.FindName("ContentPresenter", this) as ContentPresenter;
         if (contentPresenter != null)
         {
             UIElement contentVisual = VisualTreeHelper.GetChild(contentPresenter, 0) as UIElement;
             if (contentVisual != null)
             {
                 DragControl thumb = this.Template.FindName("DragControl", this) as DragControl;
                 if (thumb != null)
                 {
                     ControlTemplate template =
                         DiagramElement.GetDragControlTemplate(contentVisual) as ControlTemplate;
                     if (template != null)
                     {
                         thumb.Template = template;
                     }
                 }
             }
         }
     }
 }