Hello, I found another more subtle problem with ZClass properties. When I create two ZClasses, one of which is the parent of the other, some properties seem not be inherited properly. I create one class ("parent") with parent classes ZObject, CatalogAwareBase and ZObjectManager. This class has among others a property called "date1" of type Date. I create another class ("child") with parent classes ZObject, parent (from above) and ZDTMLDocument. Now the problem is that the date1 property is not set properly when I put a new value for "date1" an the REQUEST and call propertysheets.Basic.manage_editProperties(REQUEST) (which updates all other properties of "child" properly). Also "date1" doesn't show up in the properties tab of any "child" object. (Are inherited properties meant to do this??? If not it might be a good idea that they do. The property sheet should maybe show inherited properties in a different color etc.) However when I try to create a new property called "date1" in the "child" property sheet I get an error: "Invalid property id, date1. It is in use." Is this the right way I am using kind of multiple inheritance here? What am I doing wrong? (I am running Zope 2.3.0 on RedHat Linux 6.0) Thanks --Oliver