This is related to tracker - https://tracker.moodle.org/browse/MDL-48610
The alphabet filter at the top of the grader report page is very useful. However, it only appears when the list of students spans across two pages; if all students are able to fit on one page (e.g. if you set assignments per page to 100 and there are only 90 students to show) then the user is unable to benefit from alphabet filter.
Is anyone able to suggest a patch for this please?