The only explanation I see, is that you customized this command in the past, and it continue to show up. For special reasons, F6 has do be treated in a special way. This is why these commands are not customizable.
Do you have many custom keys? If no, erase the key shortcut file in the setting folder. Else, I can imagine some other trick.
Yes - I ditched the key shortcut file and everything has returned to normal. F6 and it’s derivatives are working.
Comment: META-SHIFT-F6 is the most annoying combo you could have chosen. It’s a huge hassle and even more so since I cannot customize it. I may roll back to 7.1.1 just for this reason alone…
It’s true this shortcut is not very practical if you use it often.
There is a third party solution, if you want to use eg. Ctrl+F6 instead.
Use this free excellent utility (good features but not that easy to setup):
and remap
Ctrl+F6 to Windows + Shift + F6.
This is done like this with AutoHotKey (I just tried it with success)
^F6::
SendInput {Shift Down}{LWin Down}{F6}{LWin Up}{Shift Up}
return
There are other keyboard utilities you could also use.
Thanks - but can you tell me why you cannot just make it practical by just making it CTRL-F6? This key combo is not in use anywhere that I can see and it’s a natural for this little cluster of F6 activities.
I won’t be wasting anytime on third party utilities just to get this the way I want it. This should not even be a discussion point. I should be able to assign this straight away and be done with it.
VP
Maybe this shortcut can be changed in the future, but since this wont happen in the near future, you have a solution now if you want to use another shortcut.
Remember also that you could also use any midi shotcut with any midi remote controller.
PG,
This is really unfortunate as you could probably fix up CTRL-F6 in about 5 minutes. I am also disappointed as you haven’t presented an effective explanation at all about why this has changed (since 7.1.1), why the key combo is such a horrific choice and most importantly - why we cannot customize this command (anymore) to our own liking.
Your usual answer to feature requests or changes from us is to have us present a logical explanation for our requests - yet here - when we ask you for one - we get nothing. Not exactly fair.
VP
Frankly, I don’t remember why I did this change. And I don’t claim this is a good change.
But the reason why it is not customizable is this one: by design, this key command can be used even if a dialog has the focus, and this needs special treatment which is not compatible with the custom shortcut system.
Well - at least you are honest 
Anyway - I will make an effort to try and not become a ham fisted moron by tying my fingers into knots doing the META-SHIFT-F6 dance…
VP