public void UnselectHandlePoint()
 {
     if (ActiveHandlePoint != null)
     {
         ActiveHandlePoint.Unselect();
         ActiveHandlePoint = null;
     }
 }
 public void SelectHandlePoint(HandlePoint handlePoint)
 {
     if (ActiveHandlePoint != null)
     {
         ActiveHandlePoint.Unselect();
     }
     ActiveHandlePoint = handlePoint;
     ActiveHandlePoint.Select();
 }