MagicDraw/Cameo: GOTCHA: ‘entry’, ‘exit’, ‘doActivity’ are all subsets of ‘ownedElement’; to use an existing Activity without changing its owner you need to create a “wrapper” Activity. Beware the tool does not simply move your Activity!

It in fact depends how you perform the assignment in the tool. If, you drag a Behavior onto a State symbol in a StateMachine Diagram it will give you a choice of whether you wish to use it as 'entry', 'doActivity', or 'exit', and will then wrap it automatically. The same applies when dragging onto a Transition symbol to assign an 'effect': However, if you use the specification dialog, and drag an Activity from the model tree into the 'effect' field of a Transition or the 'entry', 'doActivity', or 'exit' field of a State, it will move the Activity so that it is owned by the State or Transition!