diff --git a/filter/tex/displaytex.php b/filter/tex/displaytex.php
index 1a13d1c632e92..a7a986ad36209 100644
--- a/filter/tex/displaytex.php
+++ b/filter/tex/displaytex.php
@@ -1,9 +1,18 @@
-<html>
-<head><title>TeX Source</title></head>
-<body bgcolor="#FFFFFF">
-<?PHP
- $texexp = urldecode($_SERVER['QUERY_STRING']);
- echo "$texexp\n";
+<?php // $Id$
+      // This script displays tex source code.
+
+    $texexp = urldecode($_SERVER['QUERY_STRING']);
+    // entities are usually encoded twice, first in HTML editor then in tex/filter.php
+    $texexp = html_entity_decode(html_entity_decode($texexp));
+    // encode all entities
+    $texexp = htmlentities($texexp);
 ?>
-</body>
-</html>
+<html>
+  <head>
+    <title>TeX Source</title>
+    <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
+  </head>
+  <body bgcolor="#FFFFFF">
+    <?php echo $texexp; ?>
+  </body>
+</html>
\ No newline at end of file
