Hi All I have run it to a problem that feature : Event Hierarchy see doc : http://svn.boost.org/svn/boost/trunk/libs/msm/doc/HTML/ch03s02.html#d0e1108 Does not work in case of sub state machine with favor_compile_time policy. No trans get called on the sub state machine even it has a row with event type to the event base class. This now hit me badly because compiler runs out of heap if favor_compile_time policy is not used but when it is used I can not dispatch based on base type and I have about 150 different event so declare a transition for it is a no go. Is there any workaround for this problem ?. Br. Richie