Bernd, could you explain a bit more the undoStart method ? public void undoStart() { | actorId = null; | start = null; | } | especially i'm a bit concerned about the following aspects: * you set the actorId directly instead of using the setActorId(...,...) method which adds a log record and fires the assign event. is that on purpose ? * should the swimlane be updated as well ? * undo might be handled more generically by reversely playing the logs and generating compensating transactions for the updates that were logged. i didn't get to implementing this yet. but this might be something that competes with such an approach. which use case are you trying to cover with this method ? wouldn't just using the setters on actorId and start be a better approach as that wouldn't give our users the impression that this undo reverts back a lot of other things as well (e.g. variable updates that have been done between the start and the undoStart). View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4018777#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...