Okay set up a new prefix, installed the launcher, and the same problem occurs. Couldn't log in because that last section is not dissplaying. Weirdly enough I could click where I knew the LOGIN button would be and a black rectangle the size of the login dialog appeared, but without the dialog's input widgets or text. So, something's amiss. Possibly how the wine-staging-4.11 package has been built on Arch, seeing as how it works on Ubuntu? Who knows.
Ach well. ED works perfectly fine for me on wine-staging-4.10 on Arch, so I'll revert to that for now and maybe when 4.12 is released it'll be fixed.
Rgds o7