diff -urN ../roundcubemail-1.1.2.orig/program/lib/Roundcube/rcube_imap_generic.php ./program/lib/Roundcube/rcube_imap_generic.php
--- ../roundcubemail-1.1.2.orig/program/lib/Roundcube/rcube_imap_generic.php	2015-06-05 15:46:48.000000000 +0300
+++ ./program/lib/Roundcube/rcube_imap_generic.php	2015-09-27 02:48:02.000000000 +0300
@@ -2402,6 +2402,10 @@
         $headers     = array('DATE', 'FROM', 'TO', 'SUBJECT', 'CONTENT-TYPE', 'CC', 'REPLY-TO',
             'LIST-POST', 'DISPOSITION-NOTIFICATION-TO', 'X-PRIORITY');
 
+        $rcmail = rcube::get_instance();
+        $show_additional_headers = $rcmail->config->get('show_additional_headers');
+        if (is_array($show_additional_headers)) $add_headers = array_merge($add_headers, $show_additional_headers);
+
         if (!empty($add_headers)) {
             $add_headers = array_map('strtoupper', $add_headers);
             $headers     = array_unique(array_merge($headers, $add_headers));