http://bugs.winehq.org/show_bug.cgi?id=6851
--- Comment #10 from Vincent Povirk madewokherd@gmail.com 2009-03-25 16:57:52 --- Actually, wizmo is doing this:
SendMessage(HWND_TOPMOST,WM_SYSCOMMAND,SC_SCREENSAVE,0)
This is a broadcast message and (apparently) should be sent to all top-level windows. This explains why it goes to the tray window and not the desktop window.
I think that the tray window probably needs to handle this message, but someone should test this first on Windows by sending a message to the tray window directly.