Prestashop module setting form "expand" feature problem

Question

I have an multiple checkboxes and I need to hide/show it because a lot of.

array(
                'type'    => 'checkbox',
               'label'   => $this->l('Options'),
               'desc'    => $this->l('Choose options'),
               'name'    => 'options',
               'values'  => array(
                   'query' => $this->getOptions(),
                   'id' => 'id_checkbox_options',
                   'name'  => 'checkbox_options_name',
                   'expand' => array(
                       'print_total' => count($this->getOptions()),
                       'default' => 'show',
                       'show' => array('text' => $this->l('show'), 'icon' => 'plus-sign-alt'),
                       'hide' => array('text' => $this->l('hide'), 'icon' => 'minus-sign-alt')
                    ),
               ),
        ),

All working fine except 'expand' feature. Even does not generated this "plus" "minus" buttons. I don't see this button on the console. Where can be the problem?