I am sorry, but that is just too easy and not true...
Remember I also had (and still) problems with this only about 1 month ago:
May I ask: has something been changed in response in the meantime, or are you assuming that it just works?
"Typing text in a TextEditor (or in the text field of a Slider) doesn't work at all in Ableton Live or Cubase on Windows."
Now, if you say you actually made a deliberate change in the last month, I will try (again...), but it doesn't make sense to re-try every few days if we don't know you indeed tried to fix it... I think this only adds to the confusion:
Since other people on this thread are building with the latest version and don't have any problems, then it could just be that something got fixed somewhere along the line since you did your build.
This is a genuine question to obtain some clarity: did you actually try this yourself in Cubase now in the meantime?
I personally just tried this (once again) myself in Cubase 7.0.7 (last update for the Cubase 7.0 version): pulled Juce, built the plugin demo, and tested it on Windows7 in Cubase: it's not working, as before.
It's also not working in Live 9.1.1 (as before).
I understand you have lots of things to do, but please only say that you think it's fixed if you or yourself actually clearly confirmed this. Each time I read something like that, I loose half an hour of my own time to try again and agin, only to see nothing changed. Don't get me wrong: that's OK, if you can confirm you actually had a look at the issue, fixed something (and perhaps also tried it). If you still don't have a Cubase or Live NFR, PM me, and I will send you the contact info of someone at Steinberg and Ableton from whom we received our NFR.
Also, as suggested by someone else: if you could simply make the proposed add-on to the demo plugin, it would at least be very easy to test it for everyone, instead of having to make the change over and over again after each pull of the repository. I supplied the code for that in the thread I linked to above.
It would be helpful to also add a VS2010 project (and perhaps also the newer ones) to the repository, so that we don't have to do the: build Introjucer --> open Introjucer --> add VS2010 project --> save projects cycle each time.
Sorry if the above sounds a bit harsh, and I highly value your fantastic work (I truly do!), but I think it's really time the existing audio plugin stuff gets a good look at. I hope you are logging postponed issues in a bug tracking system somewhere (github has that I think) to tackle soon when you find a moment. A lot of people depend on it, and some gladly bought a commercial license because of it ;-)