If I want to do... === formDescriptionNewUserRegistration | loginDesc | loginDesc := self description copy. (loginDesc atLabel: 'Username') beWriteable; beRequired; addCondition: [ :newUserName | self client login isLoginUsernameAvailable: newUserName ] labelled: 'already taken'. ^ loginDesc ===== The copy is needed, because I dont want to modify the cached version, that everyone else is using. However, I dont think that the children are copied, they remain the same objects. Could/should they be copied in MAContainer-#postCopy ? Keith