diff --git a/core/modules/toolbar/src/Element/ToolbarItem.php b/core/modules/toolbar/src/Element/ToolbarItem.php
index aa83685..f543500 100644
--- a/core/modules/toolbar/src/Element/ToolbarItem.php
+++ b/core/modules/toolbar/src/Element/ToolbarItem.php
@@ -76,7 +76,8 @@ public static function preRenderToolbarItem($element) {
         $element['tray']['#wrapper_attributes'] = array();
       }
       $element['tray']['#wrapper_attributes'] += $attributes;
-      $element['tray']['#wrapper_attributes']['class'][] = 'toolbar-tray toolbar-tray-horizontal';
+      $element['tray']['#wrapper_attributes']['class'][] = 'toolbar-tray';
+      $element['tray']['#wrapper_attributes']['class'][] = 'toolbar-tray-horizontal';
     }
 
     $element['tab']['#attributes']['class'][] = 'toolbar-item';
diff --git a/core/modules/toolbar/toolbar.module b/core/modules/toolbar/toolbar.module
index f3e700c..ba2df53 100644
--- a/core/modules/toolbar/toolbar.module
+++ b/core/modules/toolbar/toolbar.module
@@ -293,7 +293,9 @@ function toolbar_preprocess_html(&$variables) {
   $attributes['class'][] = 'toolbar-horizontal';
   $attributes['class'][] = 'toolbar-loading';
 
-  $variables['attributes'] = new Attribute($attributes);
+  $variables['attributes'] = new Attribute(array(
+    'class' => ['toolbar-tray-open', 'toolbar-horizontal', 'toolbar-loading'],
+  ));
 }
 
 /**