There is something weird how this @DataModel functions, maybe it can be documented somewhere. In my example the @DataModel exposes the Set of a hibernate entity(from one-many relationship). If the @DataModel is a property of a stateful bean (conversation scope), then modifying the hibernate set, automatically updates the DataModel (this means that somehow seam links the DataModel to the original object; it does not clone the collection?) But if @DataModel is a property of a stateless bean, then modifying the hibernate set has no effect in the user interface. I'm confused ... it's a bug? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4054251#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...