[Zope] one 'document' in many 'folders'

[Stefan Franke]

[Pleased of having caught Jim Fulton in verbose mode 8-]

> You can store any complex Python data in the DB subject to:
[...]
>    - Subobjects of persistent objects must be "persistent" or
>     they must be immutable, or be used immutably, as in:

So class Persistent's __setattr__ is basically also the level
that transaction and undo support work on? 
Can I expect the undo support to work if I take care of the
persistence rules, regardless of cyclic and acyclic structures?

Propably about time to switch to Zope-dev...
Stefan