bug#21092: 25.0.50; Option `lazy-highlight-max-at-a-time' does not work

[Drew Adams]

> > I am interested in the general question of whether the
> > display engine precludes highlighting more than what is "on screen".
> 
> You can, of course, put the overlays or properties with some face on
> the entire buffer.  So no, the display engine doesn't preclude that.

OK, great to hear.  So this is a real Isearch bug, and there is a
possibility for it to be fixed.

Hopefully someone knowledgable will contribute to a solution.
I can try to help, but it would be great if Juri or someone else
who understands the code well could lead.