public void AddWidget(WidgetControl widget, int targetIndex = -1)
 {
     WidgetsViewModels.Add(widget.ViewModel);
     widget.ViewModel.PanelViewModel = this;
     if (targetIndex == -1)
     {
         /*View.WidgetsPanel.Children.Add(GetNewWidgetStackPanelDropPlaceHolder());
          * View.WidgetsPanel.Children.Add(widget);*/
         View.WidgetsPanel.AddElement(widget);
     }
     else
     {
         /*View.WidgetsPanel.Children.Insert(targetIndex, widget);
          * View.WidgetsPanel.Children.Insert(targetIndex, GetNewWidgetStackPanelDropPlaceHolder());*/
     }
 }