Re: Text Properties And Buffer Modification

[Eli Zaretskii]

> Date: Wed, 05 Dec 2018 20:04:25 +0100
> From: martin rudalics <address@hidden>
> CC: address@hidden
> 
>  >>> Don't forget that the modified status is important for more than
>  >>> just saving to a file: it is important for redisplaying the
>  >>> buffer, for example.
>  >>
>  >> Really?
>  >
>  > Is that a rhetorical question?
> 
> I would have thought that buffer redisplay is triggered only by
> bset_redisplay and BUF_COMPUTE_UNCHANGED which IIUC are called the
> same way for overlays and text properties.  Am I wrong?

Yes.  The display engine sometimes needs to know not only whether the
buffer needs to be redisplayed, but also _why_.  Search xdisp.c for
MODIFF, and you will see.