[Zope-dev] How do I restrict access to a Zclass property?

I notice in Zope 2.1.4 I can access a property on a Zclass instance, even if I have no permissions to the object... For example, I can say <dmtl-var "foo.title">. In regular Zope objects, this is handled by the "Access Contents Information" permission. I've poked around in the permission settings in the ZClass management screens, but haven't come across anything. Is this just not implemented yet?