I have no global roles assigned but teachers have been assigned the role 'Teacher' on the front page. I have various resources (staff briefing, detention list) on the main menu that are hidden from students but teachers can see them. However, even though they can see them, when they click to download one, Moodle gives "sorry, this activity is currently hidden". I don't know if it's that the 'Teacher' role doesn't have permissions to the site files on the home page or not.