RE: can we please define a face for compile.el mouseover?

[Drew Adams]

> > Can we please define a face to be used for the `mouse-face' 
> > property in the `compile.el' code?
> 
> Why do you want a different mouse-face in compile.el than elsewhere?

I want users to _be able_ to customize mouseover appearance differently in one
context from another.  I don't want to _require_ them to use different faces any
more than I want to require them to use the same face (the case today, and not
even customizable).

In my own case, I want mouseover in compilation/grep buffers to just underline
the text.  But I generally want mouseover to use face `highlight' elsewhere.
And on the mode line I want it to use face `mode-line-highlight' - which it does
(that's a raised box BTW - it has no relation to the mouseover appearance
elsewhere).

I also apply `mouse-face' to the whole grep/compilation line, but that's just
me.  I believe that users should get visual feedback indicating that they can
click anywhere on the line.  Also, mousing over the line anywhere (e.g. far off
to the right) highlights (underlines) the whole line, making it easy to visually
scan rows (like using a ruler) - it's especially useful with sparse table data
or code.

And of course I've mentioned all of this umpteen times in the past...
But thanks for asking. ;-)

> > It doesn't make sense to hard-code `highlight' in this code.
> > For a user to be able to use a different face for mouseover 
> > s?he needs to duplicate EACH of the
> 
> Actually, you should be able to do it cleanly using face-remapping.

Users should be able to do it by _customizing_ the particular face used for
mouseover in the particular context.  Why complicate things unnecessarily?  One
might be able to use face remapping here and there all over the place to
simulate face customization, but why?

If you think two particular contexts are similar a priori, then define their
mouseover faces to inherit the same way - same default appearance.  But at least
let the user customize them to look different if that's what s?he wants.