Update to Drupal 8.0.2. For more information, see https://www.drupal.org/drupal-8.0.2-release-notes

core/modules/editor/editor.module

@@ -238,6 +238,9 @@ function editor_form_filter_admin_format_submit($form, FormStateInterface $form_
 /**
  * Loads an individual configured text editor based on text format ID.
  *
+ * @param int $format_id
+ *   A text format ID.
+ *
  * @return \Drupal\editor\Entity\Editor|null
  *   A text editor object, or NULL.
  */

core/modules/editor/editor.routing.yml

@@ -2,6 +2,8 @@ editor.filter_xss:
   path: '/editor/filter_xss/{filter_format}'
   defaults:
     _controller: '\Drupal\editor\EditorController::filterXss'
+  options:
+    _theme: ajax_base_page
   requirements:
     _entity_access: 'filter_format.use'
 
@@ -23,6 +25,8 @@ editor.image_dialog:
   defaults:
     _form: '\Drupal\editor\Form\EditorImageDialog'
     _title: 'Upload image'
+  options:
+    _theme: ajax_base_page
   requirements:
     _entity_access: 'filter_format.use'
 
@@ -31,5 +35,7 @@ editor.link_dialog:
   defaults:
     _form: '\Drupal\editor\Form\EditorLinkDialog'
     _title: 'Add link'
+  options:
+    _theme: ajax_base_page
   requirements:
     _entity_access: 'filter_format.use'

core/modules/editor/src/Plugin/InPlaceEditor/Editor.php

@@ -59,6 +59,11 @@ class Editor extends PluginBase implements InPlaceEditorInterface {
 
   /**
    * Returns whether the text format has transformation filters.
+   *
+   * @param int $format_id
+   *   A text format ID.
+   *
+   * @return bool
    */
   protected function textFormatHasTransformationFilters($format_id) {
     $format = entity_load('filter_format', $format_id);

core/modules/editor/src/Tests/QuickEditIntegrationTest.php

@@ -111,7 +111,17 @@ class QuickEditIntegrationTest extends QuickEditTestBase {
   }
 
   /**
-   * Returns the in-place editor that Edit selects.
+   * Returns the in-place editor that quickedit selects.
+   *
+   * @param int $entity_id
+   *   An entity ID.
+   * @param string $field_name
+   *   A field name.
+   * @param string $view_mode
+   *   A view mode.
+   *
+   * @return string
+   *   Returns the selected in-place editor.
    */
   protected function getSelectedEditor($entity_id, $field_name, $view_mode = 'default') {
     $entity = entity_load('entity_test', $entity_id, TRUE);