Comment # 3 on bug 1207390 from Knut Alejandro Anderssen Gonz���lez

The problem is that the default network backend is NetworkManager and since
yast2-network-4.5.12 (https://github.com/yast/yast-network/pull/1318) we are
not copying the wicked configuration to the target system if it is not selected
as the backend during installation.

So, taking into account that the CWMFirewallInterfaces modules does not have
support for NM managed interfaces since long time ago
(https://github.com/yast/yast-yast2/commit/1d20d507b1b75b39d7f02fc8d4675265cc0e5deb)
it is grayed out.

In fact, CWMFIrewallInterfaces still relies on the NetworkInterfaces module
instead of reading and checking the network configuration from yast2-network
(Yast::Lan.yast_config).

So, we could skip or hide the firewalld configuration when NetworkManager is in
use or at least show a proper text alerting about that or we could try to
revamp the NetworkManager reader and adapt the CWMFirewallInterfaces module use
the already mentioned network configuration.