[Zope] Too early initialization of property sheets?

[John R. Daily]

Under Zope 2.3.0, with ZClasses I'm defining within Zope:

I have a method defined in a base class to loop through all property
sheets in the newly-created object and capture properties which are
stored in the REQUEST object. I invoke it during the
manage_add<product> method for inheriting classes. An example:

---
# Defined on behalf of class Foo
def manage_addFoo(id, title=""):
   foo = context.Foo.createInObjectManager(id, context.REQUEST)
   foo.private_init_defaults()
   foo.request_set_properties(context.REQUEST)
---
# Defined in inherited class VirtualFoo
def request_set_properties(REQUEST):
   sheets = container.propertysheets

   for sheet in sheets.values():
      for prop in sheet.propertyIds():
         if REQUEST.has_key(prop):
            sheet.manage_changeProperties({prop:REQUEST[prop]})
---

Unfortunately, the sheets at this point in time seem to be immutable.
I get errors which look as if property_extensible_schema__() is
returning 0.

The properties can be modified through the administrative interface
after initialization, so I'm confident that I'm not somehow
accidentally inheriting FixedSchema.

In an earlier version of this product I invoked
foo.propertysheets.default.manage_editProperties(context.REQUEST) at
the same point in manage_addFoo, but in this case I want to make
certain that all inherited property sheets are handled in an automated
fashion.

Am I approaching this in the wrong manner?

--                                                                   --
John R. Daily                                        jdaily@progeny.com
Systems Programmer                                Progeny Linux Systems
		  Master of the ephemeral epiphany