[Zope] dtml-tree does weird things

[Matt]

Hi, I have the following in a dtmlDocument.

<dtml-tree branches_expr="folder_of_things.objectValues(['Folder', 'DTML
Document'])">
   <dtml-var id>
</dtml-tree>

the folder folder_of_things contains numerous things, including some
documents and folders.  The problem seems to be that each time I expand the
tree node, I get a repeat of the original list of nodes, as if it is
listing itself recursively, but not decending down the object hierachy.

An when I roll over a node '+' of one of the documents is :
http://localhost:8080/admin_test/some_tree_examples?tree-e=eJyLVneEAteqbFt1HQUEvzLZVj0WAIkQCHY#AAAAAAAAEyc=

if I expand the tree and roll over the repeat entry I get the same link.

What's happening?

I am running 2.2.2 stable.

By they way : the simple example in the user man doesn't return anyhthing
on a folder that itself contains folders and dtml documents.  I.e.
<dtml-tree>
   <dtml-var id>
</dtml-tree>

any help would be greatly appretiated,
Matt Bion