Cannot Change Web Interface IP?

[SuperWhisk]

I have two network interfaces connected to my virtual TrueNAS box. They are both already getting ips in different subnets via DHCP (one is connected to management vlan, the other is connected to a different vlan, and all tagging is handled by the physical switch each NIC is connected to).
I want to configure the web interface ip address to just be on the management vlan, but no options are appearing other than 0.0.0.0 in System > General
Surely there is just a setting somewhere that I am missing?

 

[SuperWhisk]

Apparently only one NIC can use DHCP but this seems to be an arbitrary limitation enforced by the GUI, not an OS level issue, as it was working fine before I changed the management NIC to a static config. Adding the IP manually did make it show up as an option in System > General, but I find it ridiculous that I needed to do that in the first place.
Why can’t it simply bind the http server to whatever IP I get from DHCP on a specified NIC? Sure there’s an order of operations concern on boot, but this can surely be worked around? The interface shouldn’t be arbitrarily restricted to prevent uninformed users from making mistakes at the expense of power users who do actually know what they are doing when they bind the management GUI to a DHCP assigned IP (I have that IP statically mapped in my DHCP server on my router, I’d rather manage static IPs from a central place).