In Unified Modeling Language (UML) sequence diagrams,
an execution occurrence automatically resizes vertically to indicate
the time during which a participant is active. The top of the execution
occurrence aligns at the point where the message is received and
initiates the behavior; the bottom aligns with the finish of the
behavior during an interaction. If you resize the execution occurrence
across any messages and fragments, the execution occurrence reorders
in the interaction.
You must have a sequence diagram that contains
at least one lifeline with an execution occurrence open in the diagram editor.
Restriction: You cannot resize an execution occurrence
that has a return message attached to it.
To resize and reorder an execution occurrence, in the interaction
frame, complete one of the following steps:
- To
resize an execution occurrence, drag the handles up or down without
crossing any messages and fragments.
- To resize a nested execution occurrence, drag the handles up
or down to the maximum vertical limit of the execution occurrence
that it is nested on.
- To reorder an execution occurrence across existing messages
and fragments, drag the handles up or down.
Note: During a reorder, if you resize the
execution occurrence upward, the start point of the execution occurrence appears
before the message and fragments that you crossed. If you resize
the execution occurrence downward, the finish point of the execution
occurrence appears after the message and fragments that you crossed.