I'm running release 6.7.0.0-12 with the arguments "-multiwindow -clipboard". I run the X11 version of Emacs (from the emacs-X11-21.2-13.tar.bz2 package) which has tooltip popup windows for the toolbar icons. Even after I minimize the window, I get the tooltips if I leave the mouse where the toolbar used to be. I just wanted to report the problem; I don't know if this is a known issue. I didn't see anything about it in the mailing list archives.
Thanks, David