[Zope] Tree questions

[David Ascher]

Currently I'm using a tree tag which looks like:

<!--#tree branches_expr="objectValues(['Folder'])"-->
  <A HREF="<!--#var tree-item-url-->">        
    <!--#var title_or_id-->
  </A>
<!--#/tree-->

(stolen from the ZDP FAQ).

I'd like to modify it so that the root of the tree is fixed (as in the
help system), and so that only folders which do not have the 'hidden'
property set are shown.  

Any hints?

--david ascher