I thought I had posted this earlier today BUT I must have left without submitting
I am not an expert but the folders for the various toolbars etc are :
Quick Launch :
%AppData\Microsoft\Internet Explorer\Quick Launch
%UserProfile\Desktop and %AllUsersProfile%\Desktop
Perhaps there may be something in the folders to help find the answer.
Have you tried Safe Mode to see if they are greyed out there. If it has only happened - you could try ' My last good ..... '
I would reckon you have tried to restore defaults in the properties section of the task bar ...... probably has nothing to do with the greyed out functions.
Hope something here helps to solve the mystery. I have a greyed out function in Word which drives me mad & I still haven't found the answer........
I think taskbars do things suddenly without asking