I found this in another thread...
Re: Grades displayed by group
|I found this problem too. There is a nasty hack - I'm really new to Moodle so no idea whether this is going to break other things.
The problem seems to be in /grade/report/grader/lib.php on ~line 141
The call to setup_groups() only fires if the pref "showgroups" is set. However, I think this will only be set if the dropdown display of groups is chosen. If not (i.e. in the case when the viewer is restricted to only one group), the whole list of student participants is shown.
Taking off the if clause around setup_groups() seems to work fine for me, but I'm sure someone with a bit more knowledge could set me straight on this.
I would be willing to try this, if only I knew how to do it. Any one willing to explain it to me?