diff --git a/core/lib/Drupal/Core/Form/ConfigFormBaseTrait.php b/core/lib/Drupal/Core/Form/ConfigFormBaseTrait.php
index 1cbac3c..8380860 100644
--- a/core/lib/Drupal/Core/Form/ConfigFormBaseTrait.php
+++ b/core/lib/Drupal/Core/Form/ConfigFormBaseTrait.php
@@ -58,6 +58,14 @@ protected function config($name) {
     if (in_array($name, $this->getEditableConfigNames())) {
       // Get a mutable object from the factory.
       $config = $config_factory->getEditable($name);
+
+      // Compare editable and possibly overridden values and alert user if there
+      // are overrides that may affect this form.
+      $data = $config->get();
+      $original_data = $config_factory->get($name)->get();
+      if ($data !== $original_data) {
+        drupal_set_message(t("This form may include elements which have overridden values in your current context. Editing those values will save changes but will only be used if overrides don't apply."), 'warning');
+      }
     }
     else {
       $config = $config_factory->get($name);