Re: C-SPC works; C-u C-SPC doesn't. How could be?

[Tim Cross]

Ypo <ypuntot@gmail.com> writes:

> Thanks, Bruno
>
> I've debugged it manually because (keymap-lookup) doesn't seem to exist in my 
> emacs, if that's possible.
>
> The problem comes from:
>
> (define-key org-mode-map (kbd "C-u C-n") #'org-next-item)
>
> If I eval that line, "C-u C-SPC" stops working on org-mode. 
>
> Same problem in runemacs -q. Is it a bug?
>

You cannot use C-u like this.

The C-u is a binding to the 'universal argument'. Your line breaks that
binding so that it no longer works. What you have done is (sort of)
created a new binding which shadows the old universal argument binding
and sets up C-u as a prefix. Now, when you hit C-u emacs is waiting for
C-n. 

You will need to use some other key binding. This can be difficult as
most of the good ones are already used. Packages like free-keys can help
identify spare/unused bindings. This is one reason I like evil-mode - I
have a wealth of available bindings, most of which easy to access
without leaving the keyboard (or 'home' row). For example, in org mode,
I have j/k for down/up line, S-j/S-k for down/up heading and M-j/M-k for
down/up list item.