if(!bEnabled) { return; }
    public void mouseDown(MouseEvent e)    {        if (e.getSource() instanceof LineCanvas)        {            if (e.getSource().equals(cnvSelection))            {                toggleDropDown();            }            else            {                this.iCurrentStyle = ((LineCanvas) e.getSource()).getLineStyle();                this.cnvSelection.setLineStyle(iCurrentStyle);                this.cnvSelection.redraw();                this.cmpDropDown.getShell().dispose();                fireEvent();            }        }    }