I want to create a Python base class that inherits from the ObjectManager ZClass, since I want to have it automatically add 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. Would the appropiate way to do this be: 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? Or should I do: class MyObjectManager(ZClasses.ObjectManager.ObjectManager): propertysheets=ZClasses.ObjectManager.ZObjectManagerPropertySheets() manage_options=( {'label': 'Subobjects', 'action' :'propertysheets/subobjects/manage'}, ) and register that as the base class? -- Itamar S.T. itamars@ibm.net