It is not possible to use the pop-up-translator at the moment. Insead I only get the inline-translator. :( It would be cool to get it back.
The pop-up translation editor only works when it's needed (for example when editing qqq or on Special:Translations which doesn't yet use the inline translation editor). In all other use cases, the inline translation editor is the only option now.
That's quite a breaking change. Some kind of information on this would have been cool. However, thank you for your insight on this.
I screwed (though I'm far from the only one forgetting to announce stuff). It had been in a beta for so long while being successfully used elsewhere so I just flipped the switch.
Let's move on unless actual problems exist. Due to overlong testing, I doubt there are any.