Allowed entity types

Hello all,

During meetings, my understanding was that IDS specifications were scoped to the descendants of `IfcObject` and `IfcTypeObject`.
Now I see test cases on classes that do not inherit from these, and the documentation seems to state that every IFC class is valid.

Has this constraint changed lately or was I always mistaken?

I think the benefit of the constraint was to make editing UIs a little less intimidating for end users.

Thanks,
Claudio