public void keyReleased(KeyEvent e)
    {
        if (   e.getKeyCode() == KeyEvent.VK_UP 
                 || e.getKeyCode() == KeyEvent.VK_DOWN
                 || e.getKeyCode() == KeyEvent.VK_LEFT
                 || e.getKeyCode() == KeyEvent.VK_RIGHT ) 
        {
            switch(e.getKeyCode())
            {              
                case KeyEvent.VK_LEFT: 
                case KeyEvent.VK_RIGHT:
                    _keyDeltaX = 0;
                    break;
                case KeyEvent.VK_UP:
                case KeyEvent.VK_DOWN:
                    _keyDeltaY = 0;
                    break;  
            }
            
            dropAllGraphicsUndoable();
        }
    }