RE: highlight failed part of isearch input

[Drew Adams]

> >     It seems that only the tweaks that came out of the
> >     secondary discussion in this thread were applied; the
> >     original proposal was not.  Here is the diff.
> >
> > Would someone please apply that patch, and ack?
>
> I like this proposal but there is a problem in the patch:
>
>       (when (string-match " +$" m)
>          (propertize (substring m (match-beginning 0)) 'face
>             'trailing-whitespace))
>
> This is a no-op.  But maybe it is good to remove this code because the
> failed trailing whitespace is highlighted in the new face isearch-failed.
> We could change its background to more strong color, e.g. to something
> like is used in Firefox failed search, so failed space will be
> more visible.

Good catch. We need to change the face of the pertinent part of `m' itself,
not just a copy. Thx. The face to use for that is `trailing-whitespace', no?