public static void SendShapes(IVisio.Selection selection, VA.Selection.ShapeSendDirection dir)
 {
     if (dir == VA.Selection.ShapeSendDirection.ToBack)
     {
         selection.SendToBack();
     }
     else if (dir == VA.Selection.ShapeSendDirection.Backward)
     {
         selection.SendBackward();
     }
     else if (dir == VA.Selection.ShapeSendDirection.Forward)
     {
         selection.BringForward();
     }
     else if (dir == VA.Selection.ShapeSendDirection.ToFront)
     {
         selection.BringToFront();
     }
 }