public function config_form_definition(\MoodleQuickForm $mform) {
        $mform->addElement('header', 'header_specificsettings', get_string('specificsettings', 'customfield_select'));
        $mform->setExpanded('header_specificsettings', true);

        $mform->addElement('textarea', 'configdata[options]', get_string('menuoptions', 'customfield_select'));
        $mform->setType('configdata[options]', PARAM_TEXT);

        $mform->addElement('text', 'configdata[defaultvalue]', get_string('defaultvalue', 'core_customfield'), 'size="50"');
        $mform->setType('configdata[defaultvalue]', PARAM_TEXT);
    }