public function onSitemapNodeEdit(SitemapNodeEvent $event)
    {
        $node = $event->getNode();
        if (in_array($node->getType(), $this->textNodeTypes)) {
            $tab = new Tab(
                $event->getTranslator()->trans('text', array(), 'SilvestraTextNodeBundle'),
                'silvestra_text_node',
                $event->getRouter()->generate(
                    'silvestra_text_node',
                    array('_format' => 'json', 'nodeId' => $node->getId())
                )
            );

            $event->addTab($tab);
        }
    }