static function init()
 {
     if (is_admin()) {
         add_action('admin_menu', array(__CLASS__, 'user_menu'));
         if (is_accessareas_active_for_network()) {
             add_action('network_admin_menu', array(__CLASS__, 'user_menu'));
         }
     }
 }
 private static function _label_select_all($name, $first_element_label = false)
 {
     $network = is_accessareas_active_for_network();
     $ret = '';
     $ret .= '<select name="' . $name . '">';
     if ($first_element_label !== false) {
         $ret .= sprintf('<option value="">%s</option>', $first_element_label);
     }
     if ($network) {
         $ret .= sprintf('<optgroup label="%s">', __('Local', 'wp-access-areas'));
     }
     $ret .= self::_label_select_options(UndisclosedUserLabel::get_blog_userlabels());
     if ($network) {
         $ret .= '</optgroup>';
         $ret .= sprintf('<optgroup label="%s">', __('Network', 'wp-access-areas'));
         $ret .= self::_label_select_options(UndisclosedUserLabel::get_network_userlabels());
         $ret .= '</optgroup>';
     }
     $ret .= '</select>';
     return $ret;
 }