I have a problem with following key binding:
(global-set-key (kbd "C-/") 'comment-or-uncomment-region)
Actually, it is ignored by Emacs so undo is executed instead. I'm running Emacs in gui mode.
describe-key, I found that / is interprpeted as a
<kp-divide>, so this keybind is working like a charm now. (thanks lawlist)
(global-set-key (kbd "C-<kp-divide>") 'comment-or-uncomment-region)