public function buildExposeForm(&$form, FormStateInterface $form_state)
{
parent::buildExposeForm($form, $form_state);
// @todo There are better ways of excluding required and multiple (object flags)
unset($form['expose']['required']);
unset($form['expose']['multiple']);
unset($form['expose']['remember']);
}
public function buildExposeForm(&$form, FormStateInterface $form_state)
{
parent::buildExposeForm($form, $form_state);
$form['expose']['reduce'] = array('#type' => 'checkbox', '#title' => $this->t('Limit list to selected items'), '#description' => $this->t('If checked, the only items presented to the user will be the ones selected here.'), '#default_value' => !empty($this->options['expose']['reduce']));
}