OpenVPN 2.4 Server: Hide Interface when Protocol is Multihome
This is merely cosmetic, but may also help cut down on some confusion.
If "Protocol" is set for "<UDP/TCP> IPv4 and IPv6 on all interfaces (multihome)"
Then the "Interface" selection has no effect and is not used, so why not hide it.
Or if it's easier just force to "any" with no other options for selection could work too, but then you might get some who question why they can't change it, even though the reason is evident in the "Protocol" selection.