ACL Editor: Role not displayed at all

The first role is ROLE_INSTRUCTOR which is not available in the list of roles. That's why the role is not displayed/selected in the drop down box.

As I understood, ACLs can contain arbitrary roles ("strings") even if those roles are not in the table mh_roles.
I don't see a reason, however, to not show that roles in the ACL editor. If their not shown in the ACL editor, there is no place where a user could see the value of those ACEs in the UI.
Maybe dynamically including such roles (well, it's at most one such role per ACE) per ACE role drop down would be a feasible solution?

I am not an expert on the admin UI side but what I can see is, that roles are a controlled vocabulary which is provided by so-called list providers. The admin UI fetches both, the list of available (aka known) roles and the ACL and matches them. AFAIK there cannot be any "free" roles.

I see your point. Maybe I was a little focused on that because we are using such free roles all the time - maybe this again is because there is no interface where you ever could add roles
But removing ROLE_INSTRUCTOR at least solves to problem for the Opencast 2.1 release, which is great. Thanks!

Thanks Christoph! All roles are now shown as expected.