I downloaded and upgraded to VM workstation 15.5 from 15.1, and needed to reconfigure the network interfaces.
I use my vmnet5 for my NAT-based connections and give it a 172.17.2.0/24 scheme. After elevating my privilege, I attempt to change the default 192.x auto-assigned address to the 172.x mentioned previously, and the virtual network editor interface will not allow me to type the 172, only 17 and (bing-sound) the 2 is not allowed to be added to the first octet of my desired IP Address. At this point I cannot even go back to the 192 previously configured, as you can type 19 and (bing-error-sound) you cannot add the 2. The only option is to cancel.