Subtotal after vouchers, not before

Right now the subtotal (Zwischensumme) is shown before deducting the vouchers, it should be after instead.

Prevent deletion of ProductGroup when a Product is assigned

Throw an error message.

Don't show archived subgroups of Product groups in "Active" tab

This one is active, so it's shown: https://order.filmschoolvienna.com/dynafun/productgroup/edit/bwcdiu1o But the subgroup of it is archived, and there...

Sort ProductGroups & Products alphabetically

Sort ProductGroups alphabetically