Relate a successfully added contact to the pending contact by an event
See !51 (comment 58786):
The ContactManager method that converts a PendingContact into a Contact could broadcast an event with both IDs, if that would help?
That transaction already gets a PendingContactRemovedEvent and ContactAddedEvent attached to it. I'm guessing that in order to handle those events cleanly in the UI, you'd want the new event (let's call it a PendingContactConvertedEvent for the sake of argument) to be broadcast before the PendingContactRemovedEvent. Otherwise the UI would react to the PendingContactRemovedEvent by removing the selected item, which would no longer exist when the PendingContactConvertedEvent arrived.
If the UI will depend on the order of events for correct behaviour then the order ought to be documented in ContactManager's javadoc.