When are operations available as signatures for messages and when is it signals?
For modeling sequence diagrams, you can use the Options dialog to specify that a dialog is displayed to set the signature for the message when a message edge is placed (ARIS > Options > Designer > UML2 modeling > Set signature for new message edges).
You can also enable or disable this option using the Set signature button on the Contents tab bar.
Depending on the type of message, the dialog provides operations or signals as the signature:
If the placed message is of the Asynchronous call message or Synchronous call message type, operations are provided as the signature.
Operations are identified as follows: Target lifeline::represents -> connectable element::type -> Classifier::owned operations -> Operations.
If the placed message is of the Asynchronous signal message type, signals are provided as the signature.
Signals are identified as follows: Target lifeline::represents -> connectable element::type -> Classifier::owned receptions -> Reception::signal -> Signal.
If you do not want to set a signature, you can select the Do not set signature option.
However, if no operations or signals are found, the dialog is not displayed.