Hi, I have had problems with several objects and I suspect the problem has to do with storing complex data structures in a persistent zope object. The behavior I see is that when I display the data in the browser, sometimes it is correct (most of the time actually), but other times it is in it's initial state, as if the object had just been created. First, I tried including self._p_changed = 1 in all the object methods where the data gets modified. When that did not work, I tried changing the object's lists to persistent Zope objects, or OOBTree. That did not work. Finally, I tried changing the object data to individual ints just to see what would happen. Still the same problem. My question is, am I making a bad assumption and attaching the wrong cause of my problem? I can't think what else might be causing the problem, except possibly the fact that the application is multithreaded. But I'm pretty sure this is not causing the problem because all the data read in by one thread ALWAYS is seen as correct in the other thread, at least until the data is displayed in the browser. Thanks in advance for any suggestions. Jim Anderson