diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index 40cf74e8..47757a91 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -280,18 +280,23 @@ message at DEPTH in the current thread."
   'face 'message-mml)
 
 (defun notmuch-show-insert-part-header (nth content-type declared-type &optional name comment)
-  (insert-button
-   (concat "[ "
-	   (if name (concat name ": ") "")
-	   declared-type
-	   (if (not (string-equal declared-type content-type))
-	       (concat " (as " content-type ")")
-	     "")
-	   (or comment "")
-	   " ]\n")
-   :type 'notmuch-show-part-button-type
-   :notmuch-part nth
-   :notmuch-filename name))
+  (let ((button))
+    (setq button
+	  (insert-button
+	   (concat "[ "
+		   (if name (concat name ": ") "")
+		   declared-type
+		   (if (not (string-equal declared-type content-type))
+		       (concat " (as " content-type ")")
+		     "")
+		   (or comment "")
+		   " ]")
+	   :type 'notmuch-show-part-button-type
+	   :notmuch-part nth
+	   :notmuch-filename name))
+    (insert "\n")
+    ;; return button
+    button))
 
 ;; Functions handling particular MIME parts.