Hello, @matmarex, and thank you for your answer.Yes, it not looks like such a good way. The way I use for now, found it after sending that mail, is not good either, but seems to me a little better than this one, with hidden API.
I wrote it as
windowManager.getWindow(name)
.then(function(data) {windowManager.openWindow(data);})
// (openWindow(data) above can be also openWindow(name), it's the same)
.fail(function() {createMap(name); windowManager.openWindow(name);});
About your question, I've created a new version of Metro maps, with thumbnail in the article, that has a button, clicking on it opens a huge full version in a popup. I need this to be sure that I do not create some particular map twice, only if it wasn't created yet. I can give you some links to my code, if you're interested.
Thanks again,
Igal