Overloads the system to enable editing when a user double clicks.
        
        :param      event | <QMouseEvent>

def mouseDoubleClickEvent( self, event ):
        """
        Overloads the system to enable editing when a user double clicks.
        
        :param      event | <QMouseEvent>
        """
        super(XNavigationEdit, self).mouseDoubleClickEvent(event)
        
        self.startEdit()