bug#27517: 26.0.50; 25.2.2; Cannot add "help-echo" property to buffer regions.

[Vitalie Spinu]

Indeed. Works in other buffers.

 Vitalie

>> On Wed, Jun 28 2017 19:38, Eli Zaretskii wrote:

>> From: Vitalie Spinu <spinuvit@gmail.com>
>> Date: Wed, 28 Jun 2017 14:35:07 +0200
>> 
>>  (put-text-property (point-min) 100 'help-echo "my-mouse-over" 
>> (current-buffer))
>> 
>> No "help-ehco" property is added. Any other property (including special
>> properties) can be added.

> But only in lisp-mode, right?

> This happens because lisp-mode.el wants itself to manage the help-echo
> property:

>   (defun lisp-mode-variables (&optional lisp-syntax keywords-case-insensitive
>                                       elisp)
>   ...
>     (setq font-lock-defaults
>         `(,(if elisp '(lisp-el-font-lock-keywords
>                        lisp-el-font-lock-keywords-1
>                        lisp-el-font-lock-keywords-2)
>              '(lisp-cl-font-lock-keywords
>                lisp-cl-font-lock-keywords-1
>                lisp-cl-font-lock-keywords-2))
>           nil ,keywords-case-insensitive nil nil
>           (font-lock-mark-block-function . mark-defun)
>           (font-lock-extra-managed-props help-echo)
>            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

> When a property appears in font-lock-extra-managed-props, font-lock
> removes that property when it's about to re-fontify some region, see
> font-lock-default-unfontify-region.

> CC'ing Stefan, who made that change.