code: def mouseReleaseEvent(self, event):
          
          if event.button() == QtCore.Qt.LeftButton:
              if event.modifiers() == QtCore.Qt.ControlModifier:
                  self.goBack()
              else:
                  self.goForward()
          
          super(XWalkthroughWidget, self).mouseReleaseEvent(event)
docs: Moves the slide forward when clicked.
          
          :param      event | <QtCore.QMouseEvent>