Hi all, Excuse if this is a trivial problem. I have Zope 2.5 on NT 4.0. When I'm working on an object in ZMI and click on the view tab I have a Key error. If I open a new window browser (IE6) I can work regularly, but after some time I have this error again. Thanks to anyone can explain this error to me. This is the traceback: Traceback (innermost last): File D:\PROGRA~1\ZOPHEL~2\lib\python\ZPublisher\Publish.py, line 150, in publish_module File D:\PROGRA~1\ZOPHEL~2\lib\python\ZPublisher\Publish.py, line 114, in publish File D:\PROGRA~1\ZOPHEL~2\lib\python\Zope\__init__.py, line 158, in zpublisher_exception_hook (Object: dl_DirezionePersonale) File D:\PROGRA~1\ZOPHEL~2\lib\python\ZPublisher\Publish.py, line 98, in publish File D:\PROGRA~1\ZOPHEL~2\lib\python\ZPublisher\mapply.py, line 88, in mapply (Object: advanced_search_form) File D:\PROGRA~1\ZOPHEL~2\lib\python\ZPublisher\Publish.py, line 39, in call_object (Object: advanced_search_form) File D:\PROGRA~1\ZOPHEL~2\lib\python\OFS\DTMLMethod.py, line 127, in __call__ (Object: advanced_search_form) File D:\PROGRA~1\ZOPHEL~2\lib\python\DocumentTemplate\DT_String.py, line 473, in __call__ (Object: advanced_search_form) File D:\PROGRA~1\ZOPHEL~2\lib\python\OFS\DTMLMethod.py, line 120, in __call__ (Object: standard_html_header) File D:\PROGRA~1\ZOPHEL~2\lib\python\DocumentTemplate\DT_String.py, line 473, in __call__ (Object: standard_html_header) File D:\PROGRA~1\ZOPHEL~2\lib\python\DocumentTemplate\DT_Util.py, line 159, in eval (Object: zss_root.style()) (Info: zss_root) File <string>, line 2, in f File D:\PROGRA~1\ZOPHEL~1\lib\python\Products\ZStyleSheet\ZStyleSheet.py, line 249, in style (Object: zss_root) File D:\PROGRA~1\ZOPHEL~1\lib\python\Products\ZStyleSheet\ZStyleSheet.py, line 210, in _value (Object: zss_root) File D:\PROGRA~1\ZOPHEL~1\lib\python\Products\ZStyleSheet\ZStyleSheet.py, line 203, in _children (Object: zss_root) File D:\PROGRA~1\ZOPHEL~1\lib\python\Products\ZStyleSheet\ZSSRule.py, line 170, in _value (Object: Td_d_contents) File D:\PROGRA~1\ZOPHEL~1\lib\python\Products\ZStyleSheet\ZSSRule.py, line 162, in _children (Object: Td_d_contents) File D:\PROGRA~1\ZOPHEL~1\lib\python\Products\ZStyleSheet\ZSSAttribute.py, line 82, in _value (Object: border-right) File D:\PROGRA~1\ZOPHEL~2\lib\python\DocumentTemplate\DT_String.py, line 273, in __init__ File D:\PROGRA~1\ZOPHEL~2\lib\python\DocumentTemplate\DT_String.py, line 349, in initvars File D:\PROGRA~1\ZOPHEL~2\lib\python\ZPublisher\HTTPRequest.py, line 845, in __getitem__ File D:\PROGRA~1\ZOPHEL~2\lib\python\ZPublisher\HTTPRequest.py, line 837, in get File D:\PROGRA~1\ZOPHEL~2\lib\python\Products\Sessions\SessionDataManager.py, line 91, in getSessionData (Object: session_data_manager) File D:\PROGRA~1\ZOPHEL~2\lib\python\Products\Sessions\SessionDataManager.py, line 174, in _getSessionDataObject (Object: session_data_manager) File D:\PROGRA~1\ZOPHEL~2\lib\python\Products\Transience\Transience.py, line 133, in new_or_existing (Object: session_data) File D:\PROGRA~1\ZOPHEL~2\lib\python\Products\Transience\Transience.py, line 159, in new (Object: session_data) KeyError: duplicate key 38979001A0LXI.UStIA Thanks Michele