http://bugs.winehq.org/show_bug.cgi?id=23209
--- Comment #1 from Michael Stefaniuc mstefani@redhat.com 2010-06-18 15:57:29 --- Alexandre couldn't reproduce the problem in metacity but he is using "click to focus" and not "focus follows mouse" like I do.
So I tested it with "click to focus" and the open file dialog opens now correctly in front of the main window.