Newish to Layout Builder - we made a custom block plugin that renders a custom form. When I go to a page with Layout Builder and try to add that block... it is not in the list of blocks.

 * Provides a form block.
 * @Block(
 *   id = "my_block",
 *   admin_label = @Translation("My Block with Form"),
 *   category = @Translation("Custom")
 * )
class MyBlock extends BlockBase implements ContainerFactoryPluginInterface {

   * The form builder.
   * @var \Drupal\Core\Form\FormBuilderInterface
  protected $formBuilder;

   * Constructs a new MyBlock instance.
   * @param array $configuration
   *   The plugin configuration, i.e. an array with configuration values keyed
   *   by configuration option name. The special key 'context' may be used to
   *   initialize the defined contexts by setting it to an array of context
   *   values keyed by context names.
   * @param string $plugin_id
   *   The plugin_id for the plugin instance.
   * @param mixed $plugin_definition
   *   The plugin implementation definition.
   * @param \Drupal\Core\Form\FormBuilderInterface $form_builder
   *   The form builder.
  public function __construct(array $configuration, $plugin_id, $plugin_definition, FormBuilderInterface $form_builder) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->formBuilder = $form_builder;

   * {@inheritdoc}
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static(

   * {@inheritdoc}
  public function build() {
    $build['access_form'] = $this->formBuilder->getForm('Drupal\mymodule\Form\MyForm');
    return $build;


Is there something I need to add to the annotation or class to make it an option for Layout Builder? It works fine as a normal Drupal block.

edit: I notice in one random custom module, they have to alter Layout Builder to get this functionality. Is that correct??


1 Answer 1


This project has Layout Builder Browser installed. After adding that block to a category, it is now an option in Layout Builder. Drupal core only seems to otherwise recognize block_content blocks.

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