http://bugs.winehq.org/show_bug.cgi?id=10142
--- Comment #52 from Alex Balut alexandru.balut@gmail.com 2010-06-12 14:35:12 --- (In reply to comment #51)
That's because utorrent hides itself when minimized (and switching desktops uses minimize on most window managers), that's expected behavior. You can disable minimize to tray if you don't want that.
I disabled "minimize to tray", and it remains on the screen when I switch to another desktop and back. Tricky..