public override void RegisterGestures(GestureHandling.IGestureDispatcher dispatcher)
 {
 }
 public abstract void RegisterGestures(GestureHandling.IGestureDispatcher dispatcher);
 public override void LeaveGestures(GestureHandling.IGestureDispatcher dispatcher)
 {
 }
 public abstract void LeaveGestures(GestureHandling.IGestureDispatcher dispatcher);