Bug in BPMN2 Choreography Projector for empty choreography
A choreography is empty if it contains at least one choreography activity. The actual implementation of the utility methods isEmptyChoreography() getOneNonEmptyChoreography() and, allUsefullParticipant() consider only choreography tasks and not all the choreography activities, e.g., sub choreography.
Fix by changing the statement flowElement instanceof ChoreographyTask with flowElement instanceof ChoreographyActivity