diff --git a/core/modules/system/src/Tests/Form/ElementsTableSelectTest.php b/core/modules/system/src/Tests/Form/ElementsTableSelectTest.php
index 51771a7..c3e2d02 100644
--- a/core/modules/system/src/Tests/Form/ElementsTableSelectTest.php
+++ b/core/modules/system/src/Tests/Form/ElementsTableSelectTest.php
@@ -217,6 +217,10 @@ private function formSubmitHelper($form, $edit) {
     $form['#token'] = FALSE;
 
     $edit['form_id'] = $form_id;
+
+    // Disable page redirect for forms submitted programmatically. This is a
+    // solution to skip redirect step (there are no pages, then the redirect
+    // isn't possible).
     $form_state->disableRedirect();
     $form_state->setUserInput($edit);
     $form_state->setFormObject(new StubForm($form_id, $form));