I have added:
(global-set-key (kbd "C-z") 'undo)
~/.emacs file. But still when I press Ctrl+z nothing is undone even when I've had GNU Emacs open for a while and done several things in my present buffer. You can even see in my Edit menu that Undo isn't set to my desired keybinding: Ctrl+z.
Here is my
~/.emacs file, if relevant.