Usernames displayed like hyperlinks, but clicking them does nothing
When viewing exercise participations as an instructor or tutor, the names of the students who participated are displayed like hyperlinks. (blue, on mouseover a link is shown by the browser) Clicking this link works for administrators, but not for instructors and tutors. If they cannot interact with it, the UI should not display the names as hyperlinks. Currently, a mouseover reveals the username of the student. If this is desired, adding a message showing the username which is displayed on mouseover is a better solution. If tutors and instructors should not see a student's username, this behaviour should be removed.