>>I'm going to guess that "window.open()" didn't work well for you.
Of course I agree that any fool can open lots of browser instances (even me!) but getting them all to reflect changes in each other, was the challenge reported by the developers. I think it was to do with cross-origin communication blocked by default, but I can see that more recently, postmessage() is allowing cross-origin communication which *might* present a solution...
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
