diff --git a/core/modules/editor/src/Entity/Editor.php b/core/modules/editor/src/Entity/Editor.php
index b5dfd00..9ddc0cb 100644
--- a/core/modules/editor/src/Entity/Editor.php
+++ b/core/modules/editor/src/Entity/Editor.php
@@ -82,7 +82,7 @@ public function __construct(array $values, $entity_type) {
     $plugin = $this->editorPluginManager()->createInstance($this->editor);
 
     /* @var \Drupal\editor\Plugin\EditorPluginInterface $plugin */
-    $this->settings += $plugin->getDefaultConfiguration();
+    $this->settings = array_merge($this->settings, $plugin->getDefaultConfiguration());
   }
 
   /**