[Zope] Strange "Undo" in modifier object and not in modified object. Bug or feature ?

Hi, I got a DTML document that changes the value of a property of a folder. It works correctly on Zope 2.3.3. What'a amazing is that the "Undo" of that transaction is logged in the Undo tab of the DTML document (that's not modified) and not in the Undo tab of the folder (which a property is modified). If I "undo" the transaction from the DTML document "undo" tab, it "undoes" the change of the property of the folder... Strange isn't it ? Is it a bug or a feature ? --Gilles