Re: Weird occurrence

[Raymond Zeitler]

quasa@troy.msci.memphis.edu (Anthony Quas) writes:

[...]

> I have no idea what happened! I think I typed something but don't know
> what. Suddenly, I could see only the first couple and last couple of
> lines of the file (it was 990 lines long). Repeatedly pressing undo
> did not change the situation.
> What was stranger was that the line counter at the bottom of the
> screen still reported the correct line numbers and I could use the
> cursor keys to move up through the file without seeing it.
> I pressed C-l to redraw the screen but it didn't show anything....
> Did I suddenly put it in some weird mode??? I certainly couldn't
> detect any kind of explanation.... After doing this, I quit and
> started editing an old version of the file and everything seems fine
> again. 
> 

[...]

It /almost/ sounds as though _narrowing_ was turned on.  The only way
to turn off narrowing is to _widen_ -- undo will not undo narrowing.
Normally, narrowing is sort of disabled on first use to prevent a new
user from accidently invoking it.  But maybe you're using an
installation of Emacs on which a more experienced user enabled
narrowing, or you're using a package or mode that used it.

The whole concept of narrowing is clearly described in the Emacs
Manual.