diff --git a/mod/chat/gui_header_js/insert.php b/mod/chat/gui_header_js/insert.php
index 77e127c8a7b..799d6842c78 100644
--- a/mod/chat/gui_header_js/insert.php
+++ b/mod/chat/gui_header_js/insert.php
@@ -58,7 +58,11 @@
 
     if ($chatuser->version == 'header_js') {
         /// force msg referesh ASAP
-        echo '<script type="text/javascript">parent.jsupdate.location.href = parent.jsupdate.document.anchors[0].href;parent.input.enableForm();</script>';
+        if ($CFG->chat_normal_updatemode == 'jsupdated') {  // See bug MDL-6791
+            echo '<script type="text/javascript">parent.input.enableForm();</script>';
+        } else {
+            echo '<script type="text/javascript">parent.jsupdate.location.href = parent.jsupdate.document.anchors[0].href;parent.input.enableForm();</script>';
+        }
     }
 
     redirect('../empty.php');