> I can also be sure that all of my classes inherit these new methods/properties, even the ones that may have been subclassed from classes like CContrls. If the I-Layer is below CContrls, I'd have to change any subclasses of mine (that inherit from CContrls) to now inherit from the new I-Layer. I don't have to do that if the I-Layer is above the base MM classes.

I see, I think you're right from that perspective. Doing the whole thing this way is less common, but more practical here. Maybe we should call it a TI-Layer. Top- and Intermediate-Layer <g>.

Armin