FVWM: controlling window placement

I feel like I used to know how to do this, or maybe I didn't, and it
worked properly in the past and I've changed something unknowingly.

How do I tell CleverPlacement that some areas of the screen are off
limits?  As things are, windows often end up on top of my FvwmButtons,
and my launcher buttons.

(fvwm 2.6.8)

paul
=----------------------
paul fox, [email protected] (arlington, ma, where it's 43.0 degrees)