Issue #3467817 by roderik, junkuncz: Node 'title' field cannot be enabled in CE UI

src/Entity/EntityCeDisplay.php

@@ -2,10 +2,9 @@
 
 namespace Drupal\custom_elements\Entity;
 
+use Drupal\Core\Config\Entity\ConfigEntityBase;
 use Drupal\Core\Entity\EntityDisplayBase;
 use Drupal\Core\Entity\EntityStorageInterface;
-use Drupal\Core\Field\BaseFieldDefinition;
-use Drupal\Core\Field\FieldDefinition;
 use Drupal\Core\Plugin\DefaultLazyPluginCollection as DefaultLazyPluginCollectionAlias;
 use Drupal\custom_elements\CustomElementGenerator;
 
@@ -212,7 +211,7 @@ class EntityCeDisplay extends EntityDisplayBase implements EntityCeDisplayInterf
    * {@inheritdoc}
    */
   protected function init() {
-    // Do not call parent::init(); we don't need its display defaults.
+    // Override parent method: we don't need its display defaults.
     if (!$this->targetEntityType) {
       return;
     }
@@ -224,11 +223,11 @@ class EntityCeDisplay extends EntityDisplayBase implements EntityCeDisplayInterf
 
     $initialized = !empty($this->content) || $this->forceAutoProcessing;
     if (!$initialized) {
-      // Enable components options as done in the regular entity_view_display.
+      // Enable components that are enabled in the regular entity_view_display.
       /** @var \Drupal\Core\Entity\Display\EntityViewDisplayInterface $entity_view_display */
       $entity_view_display = \Drupal::service('entity_display.repository')
         ->getViewDisplay($this->targetEntityType, $this->bundle, $this->originalMode);
-      $field_definitions = \Drupal::service('entity_field.manager')->getFieldDefinitions($this->targetEntityType, $this->bundle);
+      $field_definitions = $this->getFieldDefinitions();
 
       // @todo Add support for statically set values.
       // Enable every component with "auto" that is enabled in the display.
@@ -312,27 +311,29 @@ class EntityCeDisplay extends EntityDisplayBase implements EntityCeDisplayInterf
    * {@inheritdoc}
    */
   public function preSave(EntityStorageInterface $storage) {
-    // Work around some of the parent code.
+    // Work around some of the parent method's code.
     $this->hidden = [];
     parent::preSave($storage);
     unset($this->hidden);
   }
 
   /**
-   * Gets the definitions of the fields that are candidate for display.
+   * {@inheritdoc}
+   */
+  public function toArray() {
+    // Skip over parent method: all fields' display is configurable, no field
+    // must be disallowed because of its definitions.
+    return ConfigEntityBase::toArray();
+  }
+
+  /**
+   * {@inheritdoc}
    */
   protected function getFieldDefinitions() {
+    // Override parent method: do not filter field definitions, all fields'
+    // display is configurable.
     if (!isset($this->fieldDefinitions)) {
-      $definitions = \Drupal::service('entity_field.manager')->getFieldDefinitions($this->targetEntityType, $this->bundle);
-
-      $this->fieldDefinitions = $definitions;
-      foreach ($this->fieldDefinitions as $field_definition) {
-        if ($field_definition instanceof BaseFieldDefinition || $field_definition instanceof FieldDefinition) {
-          // We'd like to be able to configure all the fields thus override
-          // displayConfigurable to true for all field definitions.
-          $field_definition->setDisplayConfigurable($this->displayContext, TRUE);
-        }
-      }
+      $this->fieldDefinitions = \Drupal::service('entity_field.manager')->getFieldDefinitions($this->targetEntityType, $this->bundle);
     }
 
     return $this->fieldDefinitions;