public function download_messages()
    {
        $rcmail = rcmail::get_instance();

        if ($rcmail->config->get('zipdownload_selection')) {
            $messageset = rcmail::get_uids(null, null, $multi, rcube_utils::INPUT_POST);
            if (count($messageset)) {
                $this->_download_messages($messageset);
            }
        }
    }