diff --git a/header.inc.php3 b/header.inc.php3
index 228ecdbde..4b97be06a 100755
--- a/header.inc.php3
+++ b/header.inc.php3
@@ -22,8 +22,7 @@ if ($cfg['OBGzip']) {
 $now = gmdate('D, d M Y H:i:s') . ' GMT';
 header('Expires: 0'); // rfc2616 - Section 14.21
 header('Last-Modified: ' . $now);
-header('Cache-Control: no-store, no-cache, must-revalidate'); // HTTP/1.1
-header('Cache-Control: pre-check=0, post-check=0, max-age=0'); // HTTP/1.1
+header('Cache-Control: no-store, no-cache, must-revalidate, pre-check=0, post-check=0, max-age=0'); // HTTP/1.1
 header('Pragma: no-cache'); // HTTP/1.0
 // Define the charset to be used
 header('Content-Type: text/html; charset=' . $charset);
diff --git a/left.php3 b/left.php3
index 415ca82b8..989d1d3b6 100755
--- a/left.php3
+++ b/left.php3
@@ -44,8 +44,7 @@ if ($server > 0) {
 $now = gmdate('D, d M Y H:i:s') . ' GMT';
 header('Expires: ' . $now);
 header('Last-Modified: ' . $now);
-header('Cache-Control: no-store, no-cache, must-revalidate'); // HTTP/1.1
-header('Cache-Control: pre-check=0, post-check=0, max-age=0'); // HTTP/1.1
+header('Cache-Control: no-store, no-cache, must-revalidate, pre-check=0, post-check=0, max-age=0'); // HTTP/1.1
 header('Pragma: no-cache'); // HTTP/1.0
 // Define the charset to be used
 header('Content-Type: text/html; charset=' . $charset);