private function get_display_mode_selector_html(int $displaymode) : string {
        $baseurl = $this->baseurl;
        $select = new single_select(
            $baseurl,
            'mode',
            forum_get_layout_modes(),
            $displaymode,
            null,
            'mode'
        );
        $select->set_label(get_string('displaymode', 'forum'), ['class' => 'accesshide']);

        return $this->renderer->render($select);
    }