I want to create a Python base class that inherits from the ObjectManager and has the "Subobjects" tab in the ZClass management screen. Inheriting from OFS.ObjectManager.ObjectManager does not do this - I need to inherit from ZClasses.ObjectManager.ObjectManager. I still don't know how to have the Subobjects propertysheet thing work. I've tried the two ways I listed in my last email of doing this, but I can't get it to work. One way was: class MyObjectManager(ZClasses.ObjectManager.ObjectManager): " .... " class ZMyObjectManager: """Mix-in for Object Management """ _zclass_=myObjectManager propertysheets=ZClasses.ObjectManager.ZObjectManagerPropertySheets() manage_options=( {'label': 'Subobjects', 'action' :'propertysheets/subobjects/manage'}, ) and then register ZMyObjectManager as a base class in __init__.py. The other way was: class MyObjectManager(ZClasses.ObjectManager.ObjectManager): propertysheets=ZClasses.ObjectManager.ZObjectManagerPropertySheets() manage_options=( {'label': 'Subobjects', 'action' :'propertysheets/subobjects/manage'}, ) and register that as the base class. Neither of them work. -- Itamar S.T. itamars@ibm.net