How to make a submenu for an item from a dropdown menu on yiibooster?

Question

Yii

As in the picture, the "Image" item has its own submenu

Answer 1

Specify them in the items field next to the "Images" item

Answer 2

Here is the menu, it doesn't work like that

$this->widget(
    'booster.widgets.TbNavbar',
    array(
        'type' => null,
        'brand' => 'sitel.ru',
        'brandUrl' => '/',
        'items' => array(
            array(
                'class' => 'booster.widgets.TbMenu',
                'type' => 'navbar',
                'items' => array(
                    array(
                        'icon' => 'home',
                        'label' => 'Первый пункт',
                        'url' => '#',
                        'items' => array(
                            array(
                                'label' => 'Первый подпункт',
                                'url' => '#',
                            ),
                            array(
                                'label' => 'Второй подпункт',
                                'url' => '#',
                            ),
                        ),
                    ),
                ),
            ),
...
);