Swapping out of the game to go do something in Windows (I’m running XP 64, so maybe that’s an issue?) and coming back presents me with a black blank screen with menu bars and no titles, sound still going but no way I can see to recover.
Also, I can’t update to 1.11 yet. 
Lovely game though. Just got it two days ago and haven’t stopped playing.
-JP
I’ve seen at least one other report of that with Vista (not sure which) and I have the same trouble with Windows 7 64-bit. It’s a common problem with DirectX games.
I think I might have found some info on this. From debugdata/errors.txt:
23/9/2009 - 10::26 - D3DERR_INVALIDCALL
23/9/2009 - 10::26 - D3DEngine Restore FailedThis is repeated several dozen times in my log after having tried to Alt-Tab away and back.
And now, as soon as I complain a bit, it doesn’t do it anymore. 
Yay bug fix?
My debugdata folder was empty, but that may be because I’d uninstalled/reinstalled to try to force the patch.
-JP