/**
* {@inheritdoc}
*/
public function buildForm(FormBuilderInterface $builder, array $options)
{
$categoryClassName = $this->categoryRepository->getClassName();
$builder->add('trees', 'oro_entity_identifier', ['class' => $categoryClassName, 'required' => false, 'mapped' => false, 'multiple' => true]);
$builder->add('categories', 'oro_entity_identifier', ['class' => $categoryClassName, 'required' => true, 'mapped' => true, 'multiple' => true]);
}