Command ` stopped working
At some point, I have lost the ability to use "Command `" to toggle among open pages: those listed as available in the Windows menu.
Has this function been deleted? Can I restore it? Any assistance appreciated.
First, could you check your system preferences:
System Preferences => Keyboard => Shortcuts => Keyboard => "Move focus to next window"
Does that have the checkmark to enable it and show Command-Backtick as the shortcut?
On the Firefox side:
As far as I can tell, Firefox doesn't use that as a built-in keyboard shortcut: Keyboard shortcuts - Perform common Firefox tasks quickly.
You could check whether any of your add-ons is using it. See: Manage extension shortcuts in Firefox.
This feature is also known as "Command + ~" (tilde).