Comment 2 for bug 1857928

Today I tried more combinations, once again I create new router and network.
1. Firewall group have to have some ingress policy used. If not, set someone.
2. Add firewall group in new router port.
3. Remove same port from firewall group.
4. Firewall status change to inactive or down and can be deleted.

Maybe in future you can add same rule to prevent delete ports which are used by firewall.