Thanks again.

I use the message handler MAIN::ROOT put-amount before to do some
calculations depending on the type of subclass. I could of course use
message handlers for each of subclasses, but that would require several
copies of nearly the same code. I would have prefered using the default
values for readibility, I was expecting the 'after' message-handlers to
execute after the creation of the instance.
It does not seem to have to do anything with the abstract role of the ROOT
class.
I guess using your solution is better than the work-around I was using.

Cheers