For those having the problem I had earlier, I MIGHT have figured out the problem. Maybe. If you look in %Appdata%\Adobe\AIR\ there is a ELS and a CRLCache folder where they seem to be storing some data. (The ELS may be the actual installed program even, but I'm not really sure.) When I uninstalled the GOG.com downloader, the files remained in these two directories. In the interest of a truly clean reinstall, I removed both of these. The only problem is, I did a complete reinstall. I removed AIR and the GOG downloader, redownloaded each, and reinstalled each as well as doing this, so it's hard really to be absolutely sure that this is the fix. Still, it might explain it if perhaps GOG updated or changed something significant and these cached files were no longer correct. Anyway, those experiencing the same problem might try doing this and seeing if it helps.
I still don't understand why they couldn't have used Java even. Java is a mess, but at least it's a "standard" mess that follows "normal" rules. (Eg no weird files thrown around everywhere and etc.) It's massively inefficient, but for something as simple as a downloader it's fine. (It's just something really complex such as, oh, say Minecraft, where Java is among the worst possible programming languages someone could ever choose from...) It's probably not a coincidence that one of the big torrent downloaders has always used Java. (And speaking of which, I do think they should follow the example of MMO services and use some sort of P2P downloader. This could be easier on their servers and of course would do pieces and hash checks such that corrupted downloads would be a think of the forgotten past.)
EDIT: I can confirm that deleting the files in those two folders fixes the blank window problem. Temporarily. It happened again just now, so it seems this is only a temporary fix. I deleted those files again and again the blank window went away. I suspect it will be back the very next time I run the downloader. At least a temporary fix that's annoying to deal with is better than no fix at all I guess.
Post edited March 15, 2011 by nazosan