Hi everyone, The statechart search for an event handler in post-order (children first then parent), however when we have orthogonal states involved then the behaviour I am experiencing is different. Let say we have an state X with two children [orthogonal] states Y and W. Assuming none of the handlers discard (or defer) an event, the handler for that event is called in the following order: Y, X, W, X. Note that the handler of X is called twice. The code in the following link shows that behaviour: http://coliru.stacked-crooked.com/a/14cb35ca23e586a5 If there something that I am missing? Best, Ernesto Rodriguez Reina