protected override void OnMouseLeave(EventArgs e)
 {
     base.OnMouseLeave(e);
     ControlBoxManager.ProcessMouseOperate(
         Point.Empty, MouseOperate.Leave);
 }
 protected override void OnMouseHover(EventArgs e)
 {
     base.OnMouseHover(e);
     ControlBoxManager.ProcessMouseOperate(
         PointToClient(MousePosition), MouseOperate.Hover);
 }
 protected override void OnMouseUp(MouseEventArgs e)
 {
     base.OnMouseUp(e);
     ControlBoxManager.ProcessMouseOperate(
         e.Location, MouseOperate.Up);
 }