workshop completed participants

We use some workshops for rolling intakes and completed students are causing a small issue for us.

When a student is marked as cancelled or tentative in a workshop they are moved to a tentative or cancelled list and you cannot mark their attendance. When you mark a participant as completed they remain in the confirmed list and you can still mark their attendance.

It would be helpful for us if completed students are moved to their own list and prevented from popping up in the attendance list.