Dropdown menu

Hello Everyone,

Please i would appreciate it if anyone could assist me in making the dropdown code below popup with the site's menu. It popups empty.

Thanks.

        elgg_register_menu_item('topbar', array(
            'href' => '#navigation-box',
            'rel' => 'popup',
            'class' => 'elgg-button elgg-button-dropdown',
            'text' => elgg_echo(''),
            'priority' => 101,
            'section' => 'alt',
        ));

$content = elgg_view_menu('site');

        echo elgg_view_module('dropdown', '', $content, array('id' => 'navigation-box'));