Hey Zakkar, I think I got a workaround. It seems that you need to uncheck Use Single Process and make the editor be the client (option called Editor Multiplayer Mode right under Use Single Process).
This works, but unfortunately at least on the Mac the performance is atrocious. Hopefully somebody notices this bug.
Also, keep in mind that it only works ServerTravel Map, if you pass ServerTravel Map?listen it won’t do anything.