diff --git a/core/modules/views_ui/src/ViewFormBase.php b/core/modules/views_ui/src/ViewFormBase.php
index d316e73..45d77e7 100644
--- a/core/modules/views_ui/src/ViewFormBase.php
+++ b/core/modules/views_ui/src/ViewFormBase.php
@@ -114,7 +114,7 @@ public function getDisplayTabs(ViewUI $view) {
       if (isset($display['display_options']['enabled']) && !$display['display_options']['enabled']) {
         $tabs[$id]['#link']['localized_options']['attributes']['class'][] = 'views-display-disabled-link';
       }
-      if ($view->changed_display[$id]) {
+      if (isset($view->changed_display[$id]) && $view->changed_display[$id]) {
         $tabs[$id]['#link']['localized_options']['attributes']['class'][] = 'views-display-changed-link';
       }
     }