bug#19107: 25.0.50; emacs-lisp-mode: help-echo in font-lock-extra-managed-props

[Drew Adams]

> >> I confirm this is apparently still true on ac9a931, but I don't see why
> >> it's a problem.  Could you elaborate a bit?  What exactly breaks?  What
> >> is your non-font-lock use of help-echo?
> >
> > Marcin, are you actually asking whether `help-echo' can or
> > should be used without font-lock?  If so, the answer is YES.
> 
> OK.  I didn't know (and still don't) what help-echo is for, hence my
> question.  (And I even don't know how to ask Emacs that question, aside
> from grepping the source.)

`C-h i' Elisp
`i help-echo TAB' shows you these nodes:

1. help-echo (overlay property)
2. help-echo (text property)
3. help-echo, customization keyword 
4. 'help-echo' event

(Visiting #1 also presents a link to node `Text help-echo', which
is apparently misdirected.  See bug #22986.)

(TAB will not show you #4 unless you have substring completion.
See bug #22987.  I use Icicles and `S-TAB' to see the candidates.)

If you visit those nodes you will learn how `help-echo' is used and
how you can use it yourself in your code.  If you find that the doc
for this is not clear enough please consider filing a bug report to
improve it.  Thx.