http://tech-blog.dinotools.de/2008/06/26/warum-startet-firefox-unter-linux-wine says that after upgrading to firefox 3 on linux, starting firefox would briefly open and close "a wine window", and that it was triggered by the FlashGot extension if FlashGot Options -> Advanced -> Automatic download manager detection is enabled. Whacky. I haven't tried it myself.
