/** * {@inheritdoc} */ public function validateOptionsForm(&$form, FormStateInterface $form_state) { parent::validateOptionsForm($form, $form_state); $subform = $form['entity_reference_selection']; $subform_state = new ViewsHandlerFormState($form_state); $entity_reference_selection_selector = $this->getPluginSelector($form_state); $entity_reference_selection_selector->validateSelectorForm($subform, $subform_state); }