An Action is a named element that is the fundamental unit of an executable functionality. The execution of an Action represents some transformations or processing in the modeled system, be it a computer system or otherwise. An Action execution represents the run-time Behavior of executing an Action within a specific Behavior execution. As the Action is an abstract Class, all Action executions will be the executions of a specific kind of Action. When the Action will be executed and what its actual inputs will be determined by the concrete Action and the Behaviors in which it is used.


To remove an action from a diagram by keeping incoming and outgoing control flows connected, do one of the following


  • On a diagram, select the Action and press Delete. Then, in the opened message, click Yes.
  • On a diagram, from the Action shortcut menu, select Refactor and then Remove.

  • Flows can be joined only if the removed Action has one incoming and one outgoing Control Flows.
  • You can select more than one Action to remove only if the selected part has one incoming and one outgoing Control Flow.
  • In the Environment Options dialog, in the Diagram options group, under the Editing category, you can select one of the Join Control Flows option values: Ask to join control flows, Yes, or No.


An Action can be specified by changing its property values in the Action Specification window. Each property is described in the description area on this window.