RE: C-x keystroke changed at runtime

[Drew Adams]

> I use Emacs (23.3.1 on Ubuntu 12.04) in my daily work, and I can
> assert I know it _quite_ well. Allthough today something very strange
> has happened.
> 
> After more than 1 week that it has been running (continuosly: I use to
> leave it always open, even during the night, opening and closing
> buffers, creating new frames, even with aid of emacsclient), suddenly
> (few minutes ago) the C-x keystroke has changed behavior: whenever
> there is an active region, it kills the selected text (just like C-w),
> while if there isn't any region, it acts as a prefix for the usual
> keystrokes (I can visit a file with C-x, C-f, or save it with C-x,
> C-s, or change buffer with C-x, b, for example). But with an active
> region it kills it instantly.
> 
> I am going to restart the program, but before doing it, I would be
> very curious to understand what is happening, so if anyone has a
> suggestion about some tests or checks I can do, I would appreciate.


What does `C-h v cua-mode' tell you?

Sounds like `cua-mode' is turned on.  Perhaps you have installed
a package or other Emacs-Lisp code that automatically turns on
`cua-mode', or perhaps you turned it on, yourself.

Normally, just _loading_ a library should not turn anything
on (and should not change global key bindings).  Alas, this
is not always the case.