protected override bool OnButtonPressEvent(Gdk.EventButton evnt)
 {
     if (evnt.Button == 1 && evnt.Window == GdkWindow)
     {
         var window = (Window)Toplevel;
         if (!DesktopService.GetIsFullscreen(window))
         {
             window.BeginMoveDrag(1, (int)evnt.XRoot, (int)evnt.YRoot, evnt.Time);
             return(true);
         }
     }
     return(base.OnButtonPressEvent(evnt));
 }