I'm trying to add a return message to one of my calls and it keeps giving me the error message:
"Invalid message. Please add message to lifeline."
This is confusing to me because there IS a message there on the lifeline.
Image of error
Product: Astah Community
Making the message to a synchronous one by checking off the "Asynchronous" box in the property view (left-bottom pane) will enable you to create its Reply message.