Window Manager Hints (X11) for pop-up menus

[konstan@postgres.Berkeley.EDU (Joe Konstan)]

We are trying to implement pull-down and pop-up menus using clx under
X11R3.  The window manager (TWM) is putting title bars on them which
we would prefer to avoid.  Are there WM-hints we can specify to the window
managers to request that menus (which are children of the root window) be 
completely left alone?  Also, are these TWM-specific, and is there a set of
standard window-manager hints which will work under all WMs?

Thanks for any help.

Joe Konstan
konstan@postgres.berkeley.edu