public function get_used_module_names($plural = false) {
        $modnames = get_module_types_names($plural);
        $modnamesused = array();
        foreach ($this->get_cms() as $cmid => $mod) {
            if (!isset($modnamesused[$mod->modname]) && isset($modnames[$mod->modname]) && $mod->uservisible) {
                $modnamesused[$mod->modname] = $modnames[$mod->modname];
            }
        }
        core_collator::asort($modnamesused);
        return $modnamesused;
    }