- (setq header-line-format
- (replace-regexp-in-string "%" "%%"
- (notmuch-sanitize
- (notmuch-show-strip-re
- (notmuch-show-get-subject)))))
+ (when notmuch-show-header-line
+ (setq header-line-format
+ (replace-regexp-in-string "%" "%%"
+ (notmuch-sanitize
+ (notmuch-show-strip-re
+ (notmuch-show-get-subject))))))