I do not understand how the Allow role overrides function is supposed to work. Let me describe how I expect it to work, but it doesn't. (Note: using 1.7 and 1.8).
I want to allow the teachers on my test site to override roles "under" them in the hierarchy: non-editing teacher, student, etc.
Method #1. As Admin, I go to Administration ► Users ► Permissions ► Define roles and I click on the Allow role overrides tab. On the Teacher line, I tick the Non-editing teacher, Student & Guest columns. Then I log out and log in as teacher in a course on that site. When I go to a course where I am a teacher, I go to Administration / Assign Roles, but there I can only see the Assign Roles tab, not the Override Roles tab which I would see if I were logged in as Admin.
Method #2. Of course I realize that the way to do what I want is as follows. As Admin, I go to Administration ► Users ► Permissions ► Define roles -> Manage roles -> Teacher -> Edit -> Override permissions for others: Allow.
My question is: what is the use of method #1?