It's not perfect (for some unknown reason), but thumbnails draw now.
Edge case to fix with Tweetbot-specific quirks

Or any application that's bad at naming windows, really. I wonder if I
should distinguish between empty string and no name at all?
Copy edit.
Match interface to match the currently-shipped Switch for now

Something weird with subwindows and I really want to get an update out
that fixes the first launch experience.
Well that's now been tested.
AX scaffolding and some cleanup.
Switch functions again! Time for testing and a few minor improvements to avoid regressing performance too much.