Maximum one planning time lesson per day

The planning time lessons can be inputted as lessons without class. They are shown in teacher's timetable and they are independent from any class.

Using the advanced cardrelationship you can specify that teacher can have max 1 planning time lesson per day:

Take care to specify the correct values:
- Select "Max periods per day (#10)"
- Specify max 1 per day
- Select "Apply to selected teachers"
- Specify the subject - "Planning time"