Hi. I have litte difficulties with tree tag. I'm using tree tag the way it is used in ZBook with the only difference that I'm navigating in sql method instead of Zope folder. The url is something like /whatever/sql_method/oid/7/dtml_meth_with_tree?tree-s=somethin&..... Everything works fine till some other browswer invokes some (any) method on object '/whatever'. then tree state variables become invalid, the following exception is raised: Error Type: AttributeError Error Value: 'tuple' object has no attribute 'append' and in traceback: File /local/Zope-2.0.0b6-src/lib/python/DocumentTemplate/DT_With.py, line 148, in render (Object: _.namespace(asutus_id=1)) File /local/Zope-2.0.0b6-src/lib/python/TreeDisplay/TreeTag.py, line 154, in render (Object: a tree tag) File /local/Zope-2.0.0b6-src/lib/python/TreeDisplay/TreeTag.py, line 222, in tpRender (Object: NoBrains) File /local/Zope-2.0.0b6-src/lib/python/TreeDisplay/TreeTag.py, line 538, in apply_diff (Info: ([None, ([139374408, []],)], [2])) AttributeError: (see above) Any ideas what i might be doing wrong? Have I missed some important concurrency issue? Thans in advance, Lauri Posti, Linnet Systems Ltd.