If this causes major problems for anyone, we can retract this change and rethink what should be done. We hope this system will work for everyone, because the alternative is to introduce a new language construct, map_overlays(x,y,z), just for this obscure purpose.
Heh... even if this does cause problems, I won't tell you, because I suspect the benefit of the new behavior will far outweigh any backwards-compatibility concerns. :)
From which I gather that you are experiencing backwards-compatibility problems. Darn!
--Dan