How to use WiFi on Pi3 in Ubuntu Core?

My Pi3 Nextcloud is coming together better and better. I have had it running for quite some time with stable performance with local static IP using ethernet cable.

In the long run I am unfortunately not able to keep it connected to the router by ethernet cable, so I need to get the WiFi running.

Using the network setup GUI in Ubuntu Core, the built-in WiFi adapter is only represented/shown one out of five times. If I see it there, I can scan for networks (which functions correctly), enter WPA password, enter deisred static IP, etc. BUT, when I hit ENTER to finalize the network setup, the WiFi adapter disappears from the GUI, and no WiFi connection is made. If I re-enter the setup GUI, the WiFi is still gone, and I have to re-enter a couple of time ( and maybe perform a reboot) before it is visible again, and then all the data i entered previously is gone.

Has anyone successfully used the built-in WiFi in Pi3 with Core?
Other thoughts/ideas?

It should be possible. For individual problems with your OS, ask their community. Just some searching found me this:

for ubuntu snappy-stuff: