UNABLE TO ENTER CONTROL CHARACTERS FOR A NEW KEYBOARD SHORTCUT

I'm using Indesign cc 2019 and trying to create a new 'Text' context keyboard shortcut to toggle between default and preview view mode when editing text.  The default shortcut to toggle the view mode is 'W' but of course if you're editing text and hit the 'W' key you'll simply get a letter 'W' in the text.

This seems as simple as it could get - I enter the Edit Keyboard Shortcuts panel, choose the Tools Product Area and scroll down to the 'Toggle view...' feature.  That then shows me that 'W' is the default shortcut for this feature, which I am not trying to change.

Instead, what I am trying to do is create a new 'Text' context shortcut of Opt-W which would allow me to toggle the view while still in a text editing mode. 

The problem is that I cannot enter the new shortcut keys of Opt+W in the new shortcut window. If I hit the Option Key, nothing shows up in the window. I've tried just for the sake of it to enter other combinations like Shift+W or Cmd+W just to see if the problem is limited to using the Option key. Nothing works - I cannot enter a new shortcut key combination in the New Shortcut window. I even tried doing it on a completely unrelated shortcut key in a different 'Product Area' - same result.

It appears I am missing something simple else there is a glitch in CC 2019 or my implementation of it.

Would appreciate any assistance.

Thank you!