OU Moodle with new Quiz reports
On the Responses tab.
1 Run a quiz with say 10 students.
2 Start your view with a 'page size' of 20. All students are shown.
3 Reduce your page size to 2. Only 2 students are shown. The alphabet selector is also shown.
4 Choose a starting letter for a name that no one has. 'Nothing to display' is shown.
5 Now set your page size back to 20. 'Nothing to display' is still shown but, here's the catch, the alphabet selector has disappeared so there's no way of showing any students as this page stands.