protected function page_display_options($form, $form_state)
 {
     $display_options = parent::page_display_options($form, $form_state);
     $row_plugin = isset($form_state['values']['page']['style']['row_plugin']) ? $form_state['values']['page']['style']['row_plugin'] : NULL;
     $row_options = isset($form_state['values']['page']['style']['row_options']) ? $form_state['values']['page']['style']['row_options'] : array();
     $this->display_options_row($display_options, $row_plugin, $row_options);
     return $display_options;
 }