I'm trying to add some bindings to undo-tree-visualizer-mode-map. To do so I use:

(define-key undo-tree-visualizer-mode-map (kbd "S-l") 'undo-tree-visualizer-quit)

But it doesn't work, and if I do describe-keymap afterwards I see that the binding wasn't added.

There seems to be a few keymap where this behavior happens, such as ivy-occur-mode-map and Info-mode-map as well.

Any idea why is that? And how can I add bindings to those keymaps?

  • 1
    What is describe-keymap? My emacs does not know it and I cannot find it in the elisp manual. Where does it come from?
    – NickD
    Commented Jan 27, 2020 at 1:11
  • @NickD describe-keymap is an interactive autoloaded Lisp function in ‘help-fns+.el’. It basically pretty prints all bindings to commands in a given keymap.
    – Didier A.
    Commented Jan 27, 2020 at 4:26
  • Thank you for the pointer!
    – NickD
    Commented Jan 27, 2020 at 13:41

1 Answer 1


You need to use L rather than S-l.

This is a quirk of key sequences in Emacs -- for letters (a-z), the shift modifier syntax S- won't do what you want, unless C- is also used in the sequence.

You should therefore write upper-case letters explicitly in key sequences.

See also https://stackoverflow.com/q/38180797/324105

For clarity:

(kbd "L")

(kbd "S-l")

(kbd "C-l")

(kbd "C-L")

(kbd "C-S-l")

Arguably Emacs ought to translate [33554540] to "L", or otherwise recognise it as intended, but in practice (at least at present) that doesn't happen.

  • 1
    Oh, I did not know that. That's good to know, but I also realized my mistake, I was doing eval-last-sexp but my define-key was quoted ' and somehow I was assuming it was evaluating without the quote.
    – Didier A.
    Commented Jan 27, 2020 at 4:44

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