diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index 95874bb2..203528fd 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -526,7 +526,7 @@ function is used. "
 	(define-key map "p" 'notmuch-show-previous-open-message)
 	(define-key map (kbd "DEL") 'notmuch-show-rewind)
 	(define-key map " " 'notmuch-show-advance-and-archive)
-	(define-key map (kbd "M-RET") 'notmuch-show-toggle-all)
+	(define-key map (kbd "M-RET") 'notmuch-show-open-or-close-all)
 	(define-key map (kbd "RET") 'notmuch-show-toggle-message)
 	map)
       "Keymap for \"notmuch show\" buffers.")
@@ -907,10 +907,10 @@ to stdout or stderr will appear in the *Messages* buffer."
      (not (plist-get props :message-visible))))
   (force-window-update))
 
-(defun notmuch-show-toggle-all ()
-  "Change the visibility all of the messages in the current
-thread. By default make all of the messages visible. With a
-prefix argument, make them all not visible."
+(defun notmuch-show-open-or-close-all ()
+  "Set the visibility all of the messages in the current thread.
+By default make all of the messages visible. With a prefix
+argument, hide all of the messages."
   (interactive)
   (save-excursion
     (goto-char (point-min))