RE: a emacs mode to see newline, tabs, spaces

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

> >> Is there any way to put emacs in a mode which I can 
> >> visualize newline, tab, space?
> >
> > http://www.emacswiki.org/emacs/ShowWhiteSpace
> 
> When highlighting tab characters with the following snippet 
> of code, my Gnus Group buffer becomes black-and-white only.
> 
> (require 'show-wspace)
> (add-hook 'font-lock-mode-hook 'highlight-tabs)

I know nothing about a function called `highlight-tabs'. The function defined in
show-wspace.el is `show-ws-highlight-tabs'. Is that what you meant (what you
used)?

> Same happens with the following:
> (add-hook 'font-lock-mode-hook
>           '(lambda ()
>              (font-lock-add-keywords
>               nil
>               '(("\t" 0 'trailing-whitespace prepend)))))

Again, I know nothing about `trailing-whitespace'. show-wspace.el defines this
function: `show-ws-highlight-trailing-whitespace'. 

> Any idea why?

I suspect you might be mixing things from two or more different
whitespace-display packages. If you want to use show-wspace.el to show
whitespace, follow the instructions in the file. For example:

(require 'show-wspace)
;; Highlight tabs
(add-hook 'font-lock-mode-hook
 'show-ws-highlight-tabs)
;; Highlight trailing whitespace
(add-hook 'font-lock-mode-hook
 'show-ws-highlight-trailing-whitespace)
;; Highlight non-breaking spaces
(add-hook 'font-lock-mode-hook
 `show-ws-highlight-hard-spaces')

If that approach doesn't work for you, please send me a recipe to reproduce the
problem, starting with `emacs -Q'. I don't use Gnus, so if you can provide a
simpler recipe, that's good.