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Hello,

I use theme which draw boxes around priority cookie. Before updating to
version 9.4 box was rendered just around square brackets, but since
version 9.4 it has additional space at the end.

I think it's related to the fact that org-priority face definition used
to use separate regex which didn't include space, and now it uses
variable org-priority-regexp which does include additional space
character.

;; Old
(defun org-font-lock-add-priority-faces (limit)
"Add the special priority faces."
(while (re-search-forward "^\\*+ .*?\\(\\[#\\(.\\)\\]\\)" limit t)
(add-text-properties
(match-beginning 1) (match-end 1)
(list 'face (org-get-priority-face (string-to-char (match-string 2)))
'font-lock-fontified t))))

;; New
(defun org-font-lock-add-priority-faces (limit)
"Add the special priority faces."
(while (re-search-forward org-priority-regexp limit t)
(add-text-properties
(match-beginning 1) (match-end 1)
(list 'face (org-get-priority-face (string-to-char (match-string 2)))
'font-lock-fontified t))))

(defvar org-priority-regexp ".*?\\(\\[#\\([A-Z0-9]+\\)\\] ?\\)"

Removing space before last question mark fixes my problem, but I'm not
sure it won't affect something.