+ ;; Set `buffer-invisibility-spec' to `nil' (a list), otherwise
+ ;; removing items from `buffer-invisibility-spec' (which is what
+ ;; `notmuch-show-headers-visible' and
+ ;; `notmuch-show-message-visible' do) is a no-op and has no
+ ;; effect. This caused threads with only matching messages to have
+ ;; those messages hidden initially because
+ ;; `buffer-invisibility-spec' stayed `t'.
+ ;;
+ ;; This needs to be set here (rather than just above the call to
+ ;; `notmuch-show-headers-visible') because some of the part
+ ;; rendering or body washing functions
+ ;; (e.g. `notmuch-wash-text/plain-citations') manipulate
+ ;; `buffer-invisibility-spec').
+ (when (eq buffer-invisibility-spec t)
+ (setq buffer-invisibility-spec nil))
+