http://bugs.winehq.org/show_bug.cgi?id=26283
--- Comment #4 from rocko rockorequin@hotmail.com 2012-08-07 19:35:31 CDT --- wine-1.5.10-67-g866a207 is the version from git (at least, that's what it reports itself as with wine --version).
I think the issue is in the nvidia driver, not in wine. When I dropped back to the 302.17 driver, the flickering in the menu came back. So it looks likely that this bug is not a wine bug at all, but is fixed in nvidia 304.32.