To create an interaction occurrence, choose one of the following methods.
Using the diagram toolbar button:
Click the Interaction Occurrence button
on the diagram toolbar.
Click on the diagram to create the element.
Using the diagram context menu:
In Diagram view, right click on the background.
From the context menu, select New > InteractionOccurrence.
Using the element context menu:
In the UML Navigator view, right click on the collaboration diagram.
From the context menu, select New > InteractionOccurrence.