def METHOD_NAME(self, event):
    if event.button() & Qt.LeftButton:
        pos = event.localPos()
        # TODO: press should be actuated on release...
        for index, path in enumerate(self._alignmentPaths):
            if path.contains(pos):
                if self._alignment == index:
                    self._alignment = None
                else:
                    self._alignment = index
                self.update()
                break
    else:
        super().METHOD_NAME(event)