diff --git a/phpBB/includes/functions_privmsgs.php b/phpBB/includes/functions_privmsgs.php
index 24ad5afeaf..9c4a504150 100644
--- a/phpBB/includes/functions_privmsgs.php
+++ b/phpBB/includes/functions_privmsgs.php
@@ -1966,7 +1966,7 @@ function submit_pm($mode, $subject, &$data_ary, $put_in_outbox = true)
 */
 function message_history($msg_id, $user_id, $message_row, $folder, $in_post_mode = false)
 {
-	global $db, $user, $template, $phpbb_root_path, $phpEx, $auth;
+	global $db, $user, $template, $phpbb_root_path, $phpEx, $auth, $phpbb_dispatcher;
 
 	// Select all receipts and the author from the pm we currently view, to only display their pm-history
 	$sql = 'SELECT author_id, user_id