I have an issue with the progress bar and non-editing teachers.
I have restricted non-editing teachers to their own groups with moodle/site:accessallgroups set to prevent.
However when a non-editing teacher clicks on the Progress Bar's Overview of Students button they can see all groups.
I hope this makes sense.
Having had a look at the code there appears to be an error in the file overview.php where it sets the value of $course->groupmode to 2, ie Visible Groups, regardless of the settings on the course.
I hope this is sufficient information to help resolve this. I am not a confident enough coder to resolve it myself but by changing it to 1 it does what I would expect it to.