So when I tried this, and I picked static IP, it shows ghosted information of what the phone would be getting as an address/gateway/prefix length/dns if you had stayed with DHCP.
I filled in the IP box with an address that could work on the network and the save button activated.
LG Nexus 4 (mako)
Rom: CyanogenMod 11 M7
Modem: 33/02 hybrid