How to display entity label using entity reference field checkbox form display

Question

I am working with Drupal 8. And I want to create a field of entity_reference type. The field has a reference to context_question entity. And the field is displayed fine, but without any description beside the check boxes.

The context_question entity has a label field and I want exactly the label be displayed beside the checkbox in my first entity. What should I change in the code? Or do I need to create the fieldFormatter?

$fields['context_question'] = BaseFieldDefinition::create('entity_reference')
  ->setLabel(t('Context Question'))
  ->setDescription(t('Reference to context-question-type'))
  ->setSetting('target_type', 'context_question')
  ->setDisplayOptions('view', array(
    'label' => 'above',   
    'format' => 'label',
    'weight' => 15,
  ))
  ->setDisplayOptions('form', array(
    'type' => 'options_buttons',
    'weight' => 15,
  ))
  ->setCardinality(1000)
  ->setDisplayConfigurable('form', TRUE)
  ->setDisplayConfigurable('view', TRUE);

Answer 1

I assume the context_question is your custom entity or coming from a contrib module?

There are two options:

1. Add label key to context_question entity definition under entity_keys so that Drupal\Core\Entity\Plugin\EntityReferenceSelection\DefaultSelection pick it up. See Aggregator item for reference.

2. Add a @EntityReferenceSelection plugin. You have to define one. Check TermSelection for how it is implemented for terms. It looks like this: