Advisor - special classrooms are not defined

Typical example of this problem:

You define that English lesson is divided into two groups. Each group can either stay in the the homeclassroom, or can go to the teacher's room:

But when you forget to define the rooms for your teacher, the result is that both groups can only stay in the homeclassroom - in other words these two lessons cannot be on the same period, because they require the same classroom.

This might be OK and the timetable may be completed. But many times this is not what you wanted. Especially if all your groups have to stay in home classroom.

To fix this you need to either define the special rooms, etther for teacher, or for subject or define shared rooms:

Of manually specify the other available classrooms for those lessons: