[Zope] Why is the context different for these two methods?

A DTML Method with <dtml-in "objectValues('Folder')"> returns the sub-folders of it's container folder. in the same context, A DTML Method with <dtml-in "objectIds('Folder')"> returns the sub-folders of it's container folder's parent folder. why should objectIds look to the grandparent folder? Because these are in a DTML Method, I would expect both to exaluate in the context of the containing folder. Is objectIds somehow calling it's container folders' aq_parent namespace? This would seem to violate the "containment before context" paradigm. Thanks for any enlightenment, Duke (Zope 2.6.1)