I just wanted to bring this topic back from the dead as well.
Jules’ last reply to the thread you referenced says
“Well, it was never designed for multiple sources, I’m afraid. Not sure how you’d make it do that without some redesigning.”
Frankly – if you have to choose one or the other I’d suggest loose the highlight/mouseover color when triggering notes with your mouse. Of course that’s my subjective opinion but it doesn’t look like the color changes anyway when you actually trigger a note with the GUI kb… you just get a mouseover highlight color which I dont really care about. It’s cool but if it comes at the cost of LOOSING the ability to highlight notes on the same GUI kb when triggering notes via an external device its not worth it. I’d much rather get visual feedback when triggering notes from any connected/configured external MIDI (REAL) keyboard.