Hi, I'm developing a Zope product that uses a dtml file to generate the html page. I'd like to include a dtml-tree based tree for navigation on the page. The custom object inherits from SimpleItem. When I include the follow code in the dtml file: <dtml-tree> <dtml-var id> </dtml-tree> I get the following exception: An error was encountered while publishing this resource. exceptions.KeyError Sorry, a site error occurred. Traceback (innermost last): * Module ZPublisher.Publish, line 202, in publish_module_standard * Module ZPublisher.Publish, line 150, in publish * Module ZPublisher.Publish, line 119, in publish * Module ZPublisher.mapply, line 88, in mapply * Module ZPublisher.Publish, line 42, in call_object * Module Products.WellGroup.WellGroup, line 110, in index_html * Module App.special_dtml, line 65, in __call__ * Module DocumentTemplate.DT_String, line 476, in __call__ * Module TreeDisplay.TreeTag, line 88, in render * Module TreeDisplay.TreeTag, line 192, in tpRender KeyError: 'URL' If I add a class variable called URL I then get a key error for RESPONSE. My understanding from documentation is that Item (from which SimpleItem inherits) gives the product basic dtml-tree support. I can't find any examples that spell out how to write a product that supports dtml-tree tags. Could someone point me in the right direction? Thanks, Rowan