[Zope] dtml-tree (urlparam)

[Ulla Theiss]

Dear list,
 
I have a problem using dtml-tree.
 
The page which contains a dtml-tree should show a dynamic parameter, 
passed with to url calling the dtml-tree-page.
 
page_with_dtml_tree?myparam=yup
 
Before expanding or collapsing the tree, everything works fine.
 
But if I expand or collapse it, this parameter is forgotten.
 
I found the dtml-tree-parameter urlparam, which is included in the 
expanding and collapsing widget links.
<dtml-tree urlparam="myparam=abc">
 
This works fine with hard coded strings.
 
* But my string is dynamic! *
How can I pass it?
 
<dtml-tree urlparam="myparam=<dtml-var myparam>"> produced  syntax-errors.
 
Has somebody an idea, how to pass it - or how to work around the problem?
 
Many thanks in advance,
Ulla.