When the timer finishes, hide the tooltip popup widget.
        
        :param      event | <QEvent>

def timerEvent( self, event ):
        """
        When the timer finishes, hide the tooltip popup widget.
        
        :param      event | <QEvent>
        """
        if self.currentMode() == XPopupWidget.Mode.ToolTip:
            self.killTimer(event.timerId())
            event.accept()
            self.close()
        else:
            super(XPopupWidget, self).timerEvent(event)