This will be released within the next couple weeks.

I am looking forward to this one. Being able to spawn or invoke another actor and visually see this hooked into other existing machine that was added in in the project pane will be invaluable.

I used this feature in the old viz all the time - the sequence diagrams were truly one of the most useful parts. In the Stately.ia editor, I'd love to be able to create 2 machines on screen, and then see events between them. The current focus on just 1 machine isn't really how large apps are built :)

Is https://github.com/statelyai/xstate/pull/3969 part of the effort to allow for this?

Oh yes please! The very first project I picked to use Xstate for... relies on ALL of the important action happening inside the Actors themselves, and it's unfortunate that none of this can be modeled or simulated visually with the current tooling.

I imagine this would only be possible from the root actor. Although, there was a mention of parsing source files and generating an actor tree.

In any case, this would be very helpful as it's difficult to reason about multiple actors interacting with one another when you can only construct mental models. Without this, there is an inclination to combine everything into one big actor.