Hi, I just came along another question regarding state machines and sub machines. With "typedef my_initial_event initial_event" it is possible to customize the initial event. This does not work for nested sub machines, because in those cases msm just forwards the event that triggered the state change so that we end up in the sub machines initial state. Msm does not use the specified initial event of the sub machine to trigger the initial state of the sub machine. Actually, this is exactly the behaviour what we want but is it UML conform? Do you have any idea? Best Regards, Michael