public function get_user_search_button() {
        static $count = 0;
        if (!has_capability('moodle/role:assign', $this->manager->get_context())) {
            return false;
        }
        $count++;
        $url = new moodle_url('/admin/roles/assign.php', array('contextid'=>$this->manager->get_context()->id, 'sesskey'=>sesskey()));
        $control = new single_button($url, get_string('assignroles', 'role'), 'get');
        $control->class = 'singlebutton assignuserrole instance'.$count;
        if ($count == 1) {
            $this->manager->get_moodlepage()->requires->strings_for_js(array(
                    'ajaxoneuserfound',
                    'ajaxxusersfound',
                    'ajaxxmoreusersfound',
                    'ajaxnext25',
                    'enrol',
                    'enrolmentoptions',
                    'enrolusers',
                    'enrolxusers',
                    'errajaxfailedenrol',
                    'errajaxsearch',
                    'foundxcohorts',
                    'none',
                    'usersearch',
                    'unlimitedduration',
                    'startdatetoday',
                    'durationdays',
                    'enrolperiod'), 'enrol');
            $this->manager->get_moodlepage()->requires->string_for_js('assignrole', 'role');

            $modules = array('moodle-enrol-otherusersmanager', 'moodle-enrol-otherusersmanager-skin');
            $function = 'M.enrol.otherusersmanager.init';
            $arguments = array(
                'courseId'=> $this->manager->get_course()->id,
                'ajaxUrl' => '/enrol/ajax.php',
                'url' => $this->manager->get_moodlepage()->url->out(false));
            $this->manager->get_moodlepage()->requires->yui_module($modules, $function, array($arguments));
        }
        return $control;
    }