bug#15899: 24.3.50; regression: `region' overlay is lower priority than default

[Drew Adams <drew.adams@oracle.com>]

> > ... users complaining about the effects of that, and so on and
> > so forth ad nauseam.
> 
> This will have to be solved on a package-by-package basis, like
> every contentious feature. One user complaint: change the priority
> of a package-specific overlay. More complaints to change it in
> different directions: add a user option that will set the priority
> that overlay.

Yes.

> > How can you even assume that the "region overlay priority
> > won't change", given the possibility and enough pressure from
> > users? Once out of the bottle, this genie cannot be easily put back.
> 
> Region priority will have to be set once (to 100, or something),
> documented, and then never changed again. Any changes will have to
> be made to other overlays' priorities.

Yes.  But users will also be able to change the priority of the
region overlay.

You are both right: The overlay genie is a genie, and it will
definitely be out of the bottle (Eli).  It is only the default
region overlay that needs to be defined (well).  Users changing
that or other priorities can do good and or harm.  Emacs Dev
need not change the default priority of the region (or any other)
overlay, unless it thinks that is appropriate (Dmitry).

Think isearch overlay priorities.  Have they ever changed?  Has
there been a deluge of user whining that they need to be changed?