Earlier quoted context omitted.
I started using macOS with Big Sur (still on it) and I don't understand why Apple would remove the ability to select buttons in dialog windows with the keyboard. I've googled it and it seems you used to be able to do that on macOS, but when I follow the instructions on Big Sur, I can't move the selection from the button active by default to the other one (e.g. "Ok" vs "Cancel"). That means my right hand is making run…
The enter key activates the blue (default) button, the spacebar activates the one with the focus ring around it. You can move the focus ring with tab.
1. Open TextEdit.app
2. Type some random characters.
3. Attempt to quit with Cmd+Q.
4. A dialog box shows up, prompting you to save the file. Hitting Tab just cycles between the "Save As" and "Tags" text fields. There is no way for me to select the "Delete" button with Tab.
Challenge: quit TextEdit.app in that situation with they keyboard, without using the mouse, and without saving a file.
That's a broader topic btw: Apple's apps often make the Tab button only cycle between text fields. In Safari when logging into Spotify I can't reach the "Remember me" checkbox with Tab. It only cycles between the login and password textfields and the URL bar. Luckily, other browsers don't have this flaw.