Index: program/include/rcube_imap.inc
===================================================================
--- program/include/rcube_imap.inc	(revision e02e3dc8952ab2df1338b849462a8ec1811c48b1)
+++ program/include/rcube_imap.inc	(revision 69f71ba62d8e7d77c4877b47131836ea3f52f6ee)
@@ -321,5 +321,5 @@
       $headers_cached = TRUE;
 
-	if (!is_array(a_msg_headers))
+	if (!is_array($a_msg_headers))
 		return array();