Issue #3281127 by Erik Seifert, jrockowitz, aps-Andrew: Layout cannot be saved...

   * Event render function.

   */

  public function onBuildRender(SectionComponentBuildRenderArrayEvent $event) {

    $block = $block = $event->getPlugin();

    if (!$event->inPreview()) {

      return;

    }

    $build = $event->getBuild();

    if (!isset($build['#derivative_plugin_id']) || $build['#derivative_plugin_id'] !== 'dashboard:view_embed') {

      return;

    }

    $build['content']['#post_render'] = [

      static::class . '::postRender',

    ];