bug#31695: address@hidden

[martin rudalics]

> Are you sure it's a good idea to put this on the emacs-26 branch?

Yes.  As you can see from the comment back then

      /* If the new current buffer doesn't appear in the selected
         window, go to its old point (see bug#12208).  */
      if (!EQ (XWINDOW (data->current_window)->contents, new_current_buffer))

that fix was based on the wrong assumption that data->current_window
_is_ the selected window.  It is not when data->current_window is not
on the selected frame.  That was a thinko and the fix on Emacs 26
corrects it.

> This bug is a mere annoyance, and happens with quite a peculiar frame
> configuration that's probably rarely used, judging by the time it took
> us to collect only 2 reports about it, since the bug was introduced.
> OTOH, we have a somewhat poor record regarding correctness in that
> area, so it's quite possible this fix introduces some new issue.

Maybe we didn't get more reports because some people thought that the
"annoyance" is the expected behavior.  Even the OP was "hesitant" to
file the report.

> So unless you are really, REALLY sure this should go to emacs-26, I'd
> prefer to have it on master, and let the dust settle on it before we
> decide it's TRT.

The only justifiable alternative I see is to revert the fix for
Bug#12208 on Emacs 26 since that bug is even more obscure than the
present one.

But whatever you decide the responsibility will be all mine.

martin