public function first_html_part(&$part = null, $enriched = false)
    {
        if ($this->has_html_part($enriched, $part)) {
            $body = $this->get_part_body($part->mime_id, true);

            if ($part->mimetype == 'text/enriched') {
                $body = rcube_enriched::to_html($body);
            }

            return $body;
        }
    }