Finally, I think I found the reason for this problem:
@lloydmeins changed the default filter for this table, so that only register objects without a documentation are selected. But, if there are no matching register objects, the table isn't displayed. But that's wrong.
Nik | Klampfradlerchanged title from 'My overview' shows the wrong template for teachers to "Lesson documentation" tab missing in 'My overview' for teachers
changed title from 'My overview' shows the wrong template for teachers to "Lesson documentation" tab missing in 'My overview' for teachers