public function variables()
    {
        return [
            'id'         => $this->elementId,
            'tools'      => $this->tools->render(),
            'items'      => $this->getItems(),
            'useCreate'  => $this->useCreate,
            'useSave'    => $this->useSave,
            'useRefresh' => $this->useRefresh,
        ];
    }