In Unified Modeling Language (UML) sequence diagrams,
an execution occurrence is created automatically when you create
a synchronous or an asynchronous message on a lifeline. You can
also manually create an execution occurrence to show the start and
finish behavior in an interaction.
You must have a sequence diagram with lifelines
and messages open in the diagram editor.
To create an execution occurrence manually:
- In the Palette, click Execution
Occurrence.
- Click the target lifeline at a position that does not
have an existing execution occurrence.
Note: To created a nested execution occurrence,
click the target lifeline at a position that has an existing execution occurrence.