On 2016-07-04 13:02, Eli Zaretskii wrote:
>> From: Clément Pit--Claudel <clement.pit@gmail.com>
>> Cc: Eli Zaretskii <eliz@gnu.org>, Stefan Monnier <monnier@iro.umontreal.ca>,
>>  michael_heerdegen@web.de, esq@lawlist.com
>> Date: Mon, 4 Jul 2016 12:39:50 -0400
>>
>> 2. (Keith David Bershatsky + Michael Heerdegen @ https://lists.gnu.org/archive/html/bug-gnu-emacs/2016-01/msg01013.html) Updating overlays after scrolling.  The bug thread is pretty long and subtle, but this issue has also been discussed on emacs.stackexchanged IIRC.
> 
> AFAIU, this one is not a candidate for post-redisplay hook.  Scrolling
> doesn't happen every redisplay, only some of them; and we already have
> a hook for that.

Ok. I got mislead by this message:

     From: 	Eli Zaretskii
     Subject: 	bug#22404: 25.1.50; Forcing `window-scroll-functions` to run.
     Date: 	Fri, 29 Jan 2016 16:37:16 +0200

     > From: Michael Heerdegen <address@hidden>
     > Cc: Keith David Bershatsky <address@hidden>,  address@hidden
     > Date: Fri, 29 Jan 2016 13:00:42 +0100
     >
     > Anyway, using pre-command-hook is too late for us: it's not executed
     > unless the next input arrives, so you have to hit a key until
     > decorations or whatever get updated.

     Then maybe we need a post-redisplay-hook.

But in that case, it seems that the only two currently identified use cases would be happy with a hook running after redisplay has completed in full. Let's see whether other examples pop up :)