Hi, I'm currently trying to store all of the Medicine School (I work for) events in Zope, using the Calendar product to store them. I've created from my browser a Zclass which has a propertysheet and some properties in it, and some DTML methods. I've called this class GenericEvent. I want to create 4 or five other Zclasses which only differ from the first one by their meta type and the value (not the name) of one of their properties. For example I want to create ExamEvents, CoursesEvents, and so on... Then I want to give permissions to some people to add some type of events in the database. For example I want John to be able to add (and delete) both GenericEvents and ExamEvents, while I want Jane to only be allowed to add CoursesEvents, and not be allowed to delete CoursesEvents she hasn't created. I've created my GenericEvent ZClass and it works fine, thanks to Jason Spisak, but now when I try to create other ZClasses deriving from this ZClass I can't choose it as the base class for the new classes. Can I do that from my browser (How ?) or must I do it in python ? If it's not possible I plan to add the event type as a property of GenericEvent, but then how can I deal with the different permissions I need ? thanks in advance for any hint. Jerome ALET - alet@unice.fr - http://cortex.unice.fr/~jerome Faculte de Medecine de Nice - http://noe.unice.fr - Tel: 04 93 37 76 30 28 Avenue de Valombrose - 06107 NICE Cedex 2 - FRANCE