diff -u b/core/includes/ajax.inc b/core/includes/ajax.inc --- b/core/includes/ajax.inc +++ b/core/includes/ajax.inc @@ -114,8 +114,10 @@ * Ajax event. The function will be passed parameters $form and $form_state, * and should return either a renderable array (most often a form or form * fragment), an HTML string, or an array of Ajax commands. If you return a - * renderable array or a string, or an array of Ajax commands. If you return - * an array of Ajax commands, they will be executed by the calling code. + * renderable array or a string, the value will replace the original element + * named in #ajax['wrapper'], and the output of status-messages.html.twig + * will be prepended to that element. If you return an array of Ajax commands, + * they will be executed by the calling code. * - #ajax['path']: The menu path to use for the request. This is often omitted * and the default is used. This path should map * to a controller that returns data using