Hello, I think then it's the widgets bad behavour. It should do a ``newValue = previousValue.__class__(newItems)`` instead of a dumb ``newValue = list(newItems)`` (Where available of course) The problem is when the previousValue is None so we can't determine the the type. Tuesday, June 30, 2009, 11:04:49 PM, you wrote: RI> I think it's different. If you use a zope.schem.List field RI> the widgets will store the list at once. This whould replace RI> the initial created PeristentList. (or not?) RI> In general if you store a simple list as attribute on a RI> persistent class it's fine, everything is stored. RI> If you like to append or pop from this list, then yes, you RI> will need a PersistentList otherwise the changes in the RI> list are not stored back to the DB. (right?) RI> Fazit, RI> the zope.schema.List field and the Sequence widget RI> is not compatible with initial PersitentList beause RI> the widget will probably replace the list with a RI> simple list. RI> Note, I'm not 100% sure if I'm correct. But it is at RI> least something which we have to make sure that this RI> is working. -- Best regards, Adam GROSZER mailto:agroszer@gmail.com -- Quote of the day: If you risk nothing, then you risk everything. - Geena Davis