public function addGroup($title)
    {
        $group = $this->add([new self(), 'defaultTemplate' => 'menugroup.html', 'ui' => false]);
        if (is_string($title)) {
            $group->set('title', $title);
        } else {
            if (isset($title['icon']) && $title['icon']) {
                $group->add(new Icon($title['icon']), 'Icon')->removeClass('item');
            }
            $group->set('title', $title[0]);
        }

        return $group;
    }