list of groups /sections does not scroll

[50065006]

Summary: list of groups /sections does not scroll down when adding a new person

Steps to reproduce:

1. Go to People in a course with many sections/groups
2. Add new person
3. Try to put that person in a section or group at the top of the list

Expected behavior: list of group should be possible to scroll all the way

Actual behavior: list of group first goes downwards, then flicks upwards and extends beyond the screen. Makes it impossible to reach the groups at the top of the list.

Additional notes: zooming helps.