Menu. Add new first leve item

[Belfigor]

Hi, i whant to add new 1st lvl item in menu.inc.php file.
I added such code:

        'helpdesk' => [ 
            'label' => _('Helpdesk'),
            'user_type' => USER_TYPE_ZABBIX_USER, 
            'default_page_id' => 0,
            'pages' => [ 
                [
                    'url' => '2.php', 
                    'label' => _('test2') 
                ],
                [
                    'url' => '1.php',
                    'label' => _('test1')
                ]
            ]
        ], 

Now i have new item in menu and subitems in it.
But when i selecting that item, pressing on place 1 or any other place on new item it draws perfectly. But when after that i press on any other item, for example item 2, item 1 and its subitems does not dissapear, and i have gradient in place 3, selected on the image . Please help, where i do wrong?