Moodle notification dialogues are used in various places, though currently mostly for exception displays. The new activity chooser also uses them and this is the easiest place to test them. Open a course page Open your JS console Turn editing on Open the Activity chooser Confirm that it works as expected Edit /enrol/ajax.php Add something which has no chance of being parsed by a json parser (e.g. echo "{];"; die Navigate to Course administration -> Users -> Enrolled users Confirm that an error was shown in a dialogue Confirm that no errors were thrown in the console