Hello! I have a class, which should create dynamically one tab for every folder, which was created in this class. When I click on one tab there should the index of the folder be displayed and also the other tabs. To get this work I wrote a method which changes the mange_options tuple for every object in my class and the class itself, so that the path of every tab is right. This method is called everytime the index of my class is called. Now the display of a tab should depend on a variable 'visible', which every folder gets, when he's created. This variable can be changed on the index of my class. After that the index of my class is reloaded and the deactivated tab should not appear. All this worked fine on Zope 2.5.0, but on every version higher there is a strange bug: When I change the variable and click the button, which should reload the index, the whole row of tabs disappears. When I reload the page manually by refreshing with my browser the row of tabs appears again how I wish it. In the Changelog of Zope I found the fllowing change in Version 2.5.1: - Propertysheets: Ids like 'values','keys' and 'values' are now forbidden as they break WebDAV functionality. Existing Propertysheets are not affected but I don't know, if there is a connection between this and my problem? Another less important problem is, how I can select one special tab to be emphasized. If anybody could tell me how to solve my problem, I would be very grateful. Sebastian Queißer