"Shortcut Key" in [program] > Properties won't allow entries

Hello benevolent forum participants.
For many months I've had trouble with some keyboard shortcuts. Alt + Tab won't move to another window. This happens most frequently when I'm in Chrome and want to move back to Word. But sometimes other applications are affected the same way. And the problem, even with Chrome is inconsistent. My work around is to use WindowsKey + M to minimize everything, then choose Word from my task bar. (The WindowsKey + DownArrow doesn't work for me. It just moves the content of the Chrome window down a few lines.)

I've recently discovered that I can create custom keyboard shortcuts by right-clicking the desktop shortcut for the application, and entering a shortcut in the Shortcut Key field. Yay! I thought I might use this to get to Word.
When I try to set this up, I can't: although the Shortcut Key field is not grayed out -- I can click into the field -- but can't enter text or remove the word "None" from that space.
It occurred to me that these two things might be related. What do you think?

Has anyone out there had similar issues?
It seems like such a little thing, but I hate having to manually minimize a window/Chrome just to get back to a Word document. I document computer systems (often web-based) and it's driving me nuts.

Any help would be appreciated! Thank you so much for your time. Jane

That sounds like a real bugger of a problem, never experienced any thing of this nature that lasted outside of a reboot have you tried going off a restore point. Does this happen in safe mode as well?