Ned,

> I ran the test case in MVC, from a Workspace. It did 
> complete, after I proceeded once.
> 
> When I went to examine classes, etc. later, though, I got a walkback. 
> Perhaps this will offer a clue:

Not really. All it tells us is that there's a problem but the stack is
nowhere deep enough to actually see it (it looks as if it's truncated just
where it gets interesting).

If anyone wants to look into this issue and has a couple of hours to spare
(or alternatively a _really_ small throw-away image) it would be interesting
to see where exactly it breaks. E.g., try to figure out where the "lowest
class" in the meta class hierarchy is that makes the problem happen. Since
it doesn't work for ClassDescription, can you add an iVar to Class?! To
Metaclass?! Both?! Any of its subclasses (such as ProtoObject class, Object
class, Behavior class, etc. all the way along the Metaclass hierarchy)?! I
have the suspicion that there's some singular point where it breaks down and
it would be helpful if the problem could be pin-pointed more exactly.

Cheers,
  - Andreas