Hi, I have created a zclass who in the propertysheets has same properties like string, multiple lines, etc...with some default values that i give. When i create an instance of that zclass, it has those properties with the default values, but if i change one of those values, then when i make a change to the original zclass, the instance does not reflect me any more the changes...which is okey. So the question is: There is a way to know using for example an external method or perhaps with dtml, if an instance of a zclass is different from the zclass? I try using this: getattr(self,'meta_type') but it's returning me the name of the zclass... is there any property or something wich tell me if my instance is different from my zclass? Thanks.. Edgardo