You can connect the self attribute of the window part to the promptFor: action of the prompter part to display the prompter for a window.
In addition, you can connect an AbtError object to the argument of the promptFor: action. When a method associated with a public interface action returns an AbtError instance this will cause the errorResult event to be fired rather than the normalResult. The errorResult of the event to action connection can be connected to the promptFor: action of a message prompter and, if the method returns an AbtError instance, the prompter will appear showing details of the AbtError.