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A narrow rectangle on a lifeline.
Also known as: Activation box, Focus of control bar
The UML sequence diagram notation showing the period during which a participant is executing.
Shows the period during which a participant is executing in a UML sequence diagram.
Contexts: Technical drawing, Software
Gives a diagram a vertical extent that is proportional to nothing measurable, so the bar's length is a drawing convenience and not a duration.
Contexts: Technical drawing, Software
A narrow upright rectangle drawn over a stretch of the dashed lifeline.