protected override void MousePressEvent(Qyoto.QGraphicsSceneMouseEvent arg1)
 {
     if (arg1.Button() == Qt.MouseButton.LeftButton)
     {
         m_LeftButtonDown = true;
     }
 }
 protected override void MouseReleaseEvent(Qyoto.QGraphicsSceneMouseEvent arg1)
 {
     if (arg1.Button() == Qt.MouseButton.LeftButton)
     {
         m_LeftButtonDown = false;
         var pos  = arg1.Pos();
         var pos1 = arg1.ButtonDownPos(Qt.MouseButton.LeftButton);
         if (pos != null && pos1 != null && m_ArrowRect.Contains(pos1) && pos.Y() < m_Grid.HeaderHeight && pos1.Equals(pos))
         {
             this.IsExpanded = !this.IsExpanded;
             m_Grid.ResizeAndRepositionGroups();
         }
     }
 }