A start is a starting point of the flow represented in the diagram.

A start can be created in the following diagrams:
            - 
                    Activity Diagram -  one or more per diagram 
- 
                    Statechart Diagram -  one or more per diagram 
- 
                    Interaction Overview Diagram -  one only per diagram 
 
You should not use the same start in two diagrams, and you cannot create shortcuts of starts.
Note: 
            
The start is compared and merged in the Merge Model feature, which checks that there is no additional start in 
                decomposed activities.