Make sure you can see the list of site participants as admin and list of course participants as enroled user
Change "Profile visible roles" setting and make sure the dropdown on course participants page only includes those roles (assuming there are enroled users with this role).
Click on the user name and sure in his profile you can see only the roles from this list
Make sure you can see the list of site participants as admin and list of course participants as enroled user
Change "Profile visible roles" setting and make sure the dropdown on course participants page only includes those roles (assuming there are enroled users with this role).
Click on the user name and sure in his profile you can see only the roles from this list