bug#44469: 27.1; Fontlock markup disappers when visual line is active

[Eli Zaretskii]

> From: YH Tan <astyh83@gmail.com>
> Date: Thu, 5 Nov 2020 16:19:18 +0800
> 
> I have the following setting in my `.emacs.d` folder.
> 
> ```
> (defface org-commentary
>   '((t :foreground "tan1"))
>   "Face for commentary text in org mode")
> 
> (defface org-commentary-delimiter
>   '((t :foreground "tan4"))
>   "Face for commentary text delimiter in org mode")
> 
> (defun org-add-my-extra-markup ()
>   (add-to-list 'org-font-lock-extra-keywords
>                `(,(rx (group "{{")
>                       (group (+? anything))
>                       (group "}}"))
>                  (1 '(face org-commentary-delimiter)) ;; use '(face default 
> invisible t) to make invisible
>                  (2 '(face org-commentary))
>                  (3 '(face org-commentary-delimiter)))))
> 
> (add-hook 'org-font-lock-set-keywords-hook #'org-add-my-extra-markup)
> ```
> 
> As can be seen in the sample org document below, syntax highlighting is
> unstable for the Chinese text - color disappers when the visual line is
> selected. 

Could be bug#43363.  Can you try the latest emacs-27 branch of the
Emacs Git repository?