private function print_index_content() {
        global $OUTPUT;
        $page = $this->page;

        if ($page->timerendered + WIKI_REFRESH_CACHE_TIME < time()) {
            $fresh = wiki_refresh_cachedcontent($page);
            $page = $fresh['page'];
        }

        // navigation_node get_content calls format string for us
        $node = new navigation_node($page->title);

        $keys = array();
        $tree = array();
        $tree = wiki_build_tree($page, $node, $keys);

        $table = new html_table();
        $table->head = array(get_string('pageindex', 'wiki') . $OUTPUT->help_icon('pageindex', 'wiki'));
        $table->attributes['class'] = 'generalbox table';
        $table->data[] = array($this->render_navigation_node($tree));

        echo html_writer::table($table);
    }