bug#9432: 24.0.50; doc string of `next-error-highlight'

[Stefan Monnier]

> 3. FWIW3: in Emacs -Q, even if I already have the target source file
> in a separate frame (e.g. from `C-x 5 b' after having shown it once in
> the same frame), and even if that is the *only* place it is currently
> displayed, `C-x `' or hit `RET' or click a hit in *grep* still pops up
> the source file in the same frame as *grep* and highlights the hit
> there (does not even highlight it in both places).

> The already displayed source buffer should obviously be used, instead of
> multiplying things unnecessarily.  Or the behavior should be optional, under
> user control, and the default should be to show hits in a window already
> displaying the source buffer.

It's optional, controlled by display-buffer-reuse-frames.  The default
is nil, largely for historical reasons.


        Stefan