Comment 18 for bug 349336

If I'm not missing anything here, the cancel response code is not important.

The rest of the code goes on with this;

        dialog.show_all()
        response = dialog.run()
        dialog.hide()
        if response != self.gtk.RESPONSE_YES:
            self.update_sensitive()
            return

        cleaner = Cleaner(self, crufts, self.pm.get_plugins())
        cleaner.start()