http://bugs.winehq.org/show_bug.cgi?id=32948
--- Comment #3 from Sebastien Bariteau numkem@gmail.com 2013-02-11 13:20:48 CST --- I'm running Arch Linux so I have the latest right now (1.5.23-2).
I've also tried with a 64 bits wine prefix and it does the same thing for office. With other software I'm not experiencing this issues since I get the generic file dialog from Wine.