Subject: bug#73607: 30.0.90; Strange behaviour of C-x with define-prefix-command

From: Eli Zaretskii <[email-masked]>
Date: Thu, 03 Oct 2024 14:22:43 +0300

> From: Sean Whitton <[email-masked]>
> Cc: [email-masked]
> Date: Thu, 03 Oct 2024 15:13:52 +0800
> 
> Hello,
> 
> On Thu 03 Oct 2024 at 10:05am +03, Eli Zaretskii wrote:
> 
> >> From: Sean Whitton <[email-masked]>
> >> Date: Thu, 03 Oct 2024 10:42:05 +0800
> >>
> >> 1. emacs -q
> >> 2. (global-set-key "\C-z" (define-prefix-command 'foo))
> >> 3. C-z C-c => "C-z C-c is undefined" as expected
> >>
> >> However:
> >>
> >> 4. C-z C-x => "C-z C-x- (C-h for help)"
> >> 5. C-z C-x C-h => "No commands with a binding that start with C-z C-x."
> >
> > Why is that a problem?
> 
> It should say "C-z C-x is undefined" right away, like with every other key.

C-x is not like other keys, it is handled specially.  I think.