Using both moodle 1.8.2 and 1.9 I cannot as Admin set Teacher over-ride.
Logged in as Admin I go to Administration ► Users ► Permissions ► Define roles -> Allow rode overrides tab. On the Teacher row I tick the Student column. I logout and log in as Teacher and go to one of my courses. I go to the Administration block -> Assign roles. On that page I only see Roles and the Assign Roles tab, there is no Override roles tab available. What am I missing?