'Handles a item change in the quickpanel:
Calls the handler if the item is below the offset.
Otherwise it opens the file and highlights the command.'

def _on_changed(self, index):

    if (index < self._offset):
        key = self.captions[index]
        handle = self.change_handler.get(key, (lambda : None))
        handle()
        return
    self._remove_highlight()
    self._open_transient(self.entries[(index - self._offset)])
