Hey Till,
>>>> So 10.10. is definitely a "no go"...<<<<
It was a couple of years ago now when I tried it, but yeah, I think you said it when you mentioned "Was there ever a fix for the GUI issues?". That's pretty much how I remember it being. Major graphics issues.
>>>> Yes I'm interested in this oddity. <<<<
It's the only thing I've ever noticed between Mavericks and PT 10.3.10, but it's regular everyday. I run Both Reason and Vienna Ensemble Pro alongside ProTools. When I've finished with a session and I want to quit out, the best order for my setup is to quit Reason, followed by quit ProTools, followed by quit VEP.
This would normally be very straight forward ie: "Apple+Tab" to Reason. "Apple+Q" to quit. Then it should automatically flip back to the last application in the "Apple+Tab" list (you know when you get that horizontal layout of all your open programs and they cycle through every time you hit the Tab key while holding down the Apple key), which theoretically would be ProTools. But it doesn't show that. It technically HAS flipped back to PT, but in the menu top left hand corner where it shows the currently front most program, it always shows something else like VEP or even Finder. If I actually hit Apple+Q it does quit ProTools, it's just that the menu doesn't think PT is front most for some odd reason.
None of this affects anything at all operationally, it's just a display anomaly. Hope any of that made sense at all.
Cheers.
Steve