bug#21869: Redisplay: after echo area diminishes in size, Follow Mode windows aren't resynchronised.

[Alan Mackenzie]

Hello, Martin.

On Mon, Nov 09, 2015 at 11:04:16AM +0100, martin rudalics wrote:
>  > Follow Mode puts a function on window-scroll-functions which should be

> I suppose you mean ‘window-size-change-functions’.

Yes, that was what I meant.  Sorry about the inaccuracy.

>  > called any time

> Not really.

>  > a window changes size.  At the C-f above,
>  > window-size-change-functions is not being invoked.

>  > The one single place where window-size-change-functions is invoked is in
>  > the function prepare_menu_bars in xdisp.c.

>  > The one single place where prepare_menu_bars is called is fairly early on
>  > in redisplay_internal, at L+137.  This is before the echo area is resized
>  > at L+164.  Thus, the check on changed window sizes happens too early,
>  > before the change in the echo area size.

> Probably bug#830 and bug#21333.

Yes, probably.  What this bug might add to the debate is that here, the
misalignment of the windows persists after the echo area returns to its
normal size.

It is not good that window-size-change-functions gets called when the
echo area expands, but not when it shrinks again.  This is unsymmetric.

> martin

-- 
Alan Mackenzie (Nuremberg, Germany).