The keyboard shortcut to open the Keyboard Shortcuts modal conflicts with native shortcuts

[afercia]

Follow up to #8316

Pressing ctl+option+h (shift+alt+h on windows/linux) displays a modal detailing keyboard shortcuts.

When VoiceOver is running, ctrl+option+h opens the VoiceOver help and the modal doesn't open at all:

shift+alt+h on Windows opens the Firefox and IE11 Help menu: the modal opens but focus is on the browser's menu:

[afercia]

Re: shift+alt+h on Windows, worth noting in the Classic Editor it works and it opens the TinyMCE help without opening also the browser's Help menu (I guess it prevents default?).

[tofumatt]

Would using ? (and Control+?, mainly for when an input has focus) as shortcuts be alright? They don't seem to be used by the OSes for anything and sites like Trello and GitHub use them (see #10914).

[afercia]

This is still a problem:

• on Windows, Shift Alt H opens the browser's help menu in Firefox and IE11
• on macOS with VoiceOver running, Control Option H opens the VoiceOver help, see also Keyboard shortcuts that use the access modifier don't work with VoiceOver #11154

[afercia]

Related: #3218

[paaljoachim]

Is this issue still valid @joedolson ?
If so how can we move forward with it?
Thanks!

[afercia]

Closing in favor of #15335 (which comes from the WPCampus accessibility audit).