http://bugs.winehq.org/show_bug.cgi?id=7585
--- Comment #45 from Andrew Charles Hurst a.hurst@shef.ac.uk 2008-06-19 13:26:56 --- The mem hack patch doesn't fix it I'm afraid..
Have you talked to Thunderbird (Roderick) about this? I had quite a long discussion with him about it when I first filed this bug: he seemed to understand the problem pretty well.