Adds the inputed action to this toolbar.
        
        :param      action | <QAction>

def addAction(self, action):
        """
        Adds the inputed action to this toolbar.
        
        :param      action | <QAction>
        """
        super(XDockToolbar, self).addAction(action)
        
        label = XDockActionLabel(action, self.minimumPixmapSize(), self)
        label.setPosition(self.position())
        
        layout = self.layout()
        layout.insertWidget(layout.count() - 1, label)