Re: hi-lock and overlays

[Stefan Monnier]

>   - Why does hi-lock use two different styles of highlighting?  IMO, if
>     a user does M-x highlight-regexp RET foo RET hi-yellow RET, he
>     expects to get that highlighting even if there are other overlays,
>     so creating an overlay (and maybe even setting a priority) is the
>     only safe bet.

overlays are implemented inefficiently, so if you have many of them,
redisplay, buffer modifications, and other operations can become
noticeably slower.


        Stefan