bug#64177: outline-minor-mode-highlight fails to activate for custom headings

[Juri Linkov]

> I have done this and still showing failure upon 'override
>
> (defvar elisp-hglevels
>   '( (";;; H1" . 1) (";;; H2" . 2) (";;; H3" . 3) (";;; H4" . 4)
>      (";;; H5" . 5) (";;; H6" . 6) (";;; H7" . 7) (";;; H8" . 8) ))
> ...
>     ((eq major-mode 'emacs-lisp-mode)
> ...
> (outline-minor-mode 0)
> (setq outline-minor-mode-highlight 'override)
> (outlhg-regexp)
> (outlhg-tyface)
> (outline-minor-mode 1)

Please also try:

  (setq-local outline-level 'outline-level)

because 'emacs-lisp-mode' overrides the default value
with own 'lisp-outline-level'.