[Zope] How to tree from top?

[Loren Stafford]

I want to make a tree for navigation that always starts from the topmost
object regardless of the level of the current object.

But what is the ID of the topmost object?

I tried <!--#tree "PARENTS[-1]" -->, but that gets an error.

I tried enclosing the tree in <!--#with "PARENTS[-1]"--> but that doesn't
work either.

Zope 1.10

-- Thanks
-- Loren