http://bugs.winehq.org/show_bug.cgi?id=35361
--- Comment #23 from Vitor Antunes vitor.hda@gmail.com --- Applied both patches on top of wine 1.7.12 and overlay no longer crashes in both cases.
Don't know if this is relevant, but I've noticed that the first shift-click is ignored. But I did not test it on Windows, so it may be possible that this is an issue with Steam itself.