plasma 5 - Can't connect to WiFi anymore

Got hit by the plasma 5 update by surprise - for some reason zypper dup only installed half of it. Had to run it a second time with a LAN cable plugged in to get Network Manager back. But I’m still having problems:

When I click on the Network Manager widget, I get a list of available Networks, but when I hit the “Connect” button, nothing happens. Any ideas where Network Manager stores its logs? It’ pretty annoying to have your network connection fail without even the hint of an error message. When a cable is plugged in, everything works fine, but that’s not the point of having a laptop computer, is it?