unseen only if `rmail-summary-put-back-unseen' is non-nil.
;; If we first saw the previous message in this search,
;; and we have gone to a different message while searching,
;; put back `unseen' on the former one.
+ (if rmail-summary-put-back-unseen
(rmail-set-attribute "unseen" t
- rmail-current-message)
+ rmail-current-message))
;; Arrange to do that later, for the new current message,
;; if it still has `unseen'.
(setq rmail-summary-put-back-unseen