Tab Key Not Working to Select Controls I have Use keyboard navigation to move focus between controls selected in System Preferences, so but the tab key isn't working to select different controls (such as drop-down menus and checkboxes) in application dialog boxes. For example, I tried the Preview Preferences dialog box.

I have tried multiple different applications, and I do not to my knowledge have any additional software running that would be intercepting the tab key press.

Is this a problem that is local to my computer, or am I missing something important?

MacBook Pro running macOS Catalina 10.15.2
The only solution I've discovered seems to be using fn+ctrl+F7 to toggle dialog navigation on/off. It might reset after restarting the computer, but it seems to enable navigation in all applications.