diff --git a/reference/session/functions/session-unregister.xml b/reference/session/functions/session-unregister.xml
index 5472d66024..a7ef26c0e7 100644
--- a/reference/session/functions/session-unregister.xml
+++ b/reference/session/functions/session-unregister.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.4 $ -->
+<!-- $Revision: 1.5 $ -->
 <!-- splitted from ./en/functions/session.xml, last change in rev 1.2 -->
   <refentry id="function.session-unregister">
    <refnamediv>
@@ -28,7 +28,9 @@
       If <varname>$_SESSION</varname> (or
       <varname>$HTTP_SESSION_VARS</varname> for PHP 4.0.6 or less) is
       used, use <function>unset</function> to unregister a session
-      variable.
+      variable. Do not <function>unset</function> <varname>$_SESSION</varname>
+      itself as this will disable the special function of the
+      <varname>$_SESSION</varname> superglobal.
      </para>
     </note>
     <caution>
diff --git a/reference/session/functions/session-unset.xml b/reference/session/functions/session-unset.xml
index 54e1ceb9c4..02ee27df9b 100644
--- a/reference/session/functions/session-unset.xml
+++ b/reference/session/functions/session-unset.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.3 $ -->
+<!-- $Revision: 1.4 $ -->
 <!-- splitted from ./en/functions/session.xml, last change in rev 1.8 -->
   <refentry id="function.session-unset">
    <refnamediv>
@@ -26,6 +26,16 @@
       variable. i.e. $_SESSION = array();
      </para>
     </note>
+    <para>
+     <caution>
+      <para>
+       Do NOT unset the whole <varname>$_SESSION</varname> with
+       <literal>unset($_SESSION)</literal> as this will disable the
+       registering of session variables through the
+       <varname>$_SESSION</varname> superglobal.
+      </para>
+     </caution>
+    </para>
    </refsect1>
   </refentry>
 
diff --git a/reference/session/reference.xml b/reference/session/reference.xml
index 4de9e9fcae..a2330b2eed 100644
--- a/reference/session/reference.xml
+++ b/reference/session/reference.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.36 $ -->
+<!-- $Revision: 1.37 $ -->
  <reference id="ref.session">
   <title>Session handling functions</title>
   <titleabbrev>Sessions</titleabbrev>
@@ -200,6 +200,18 @@ unset($_SESSION['count']);
 ]]>
       </programlisting>
      </example>
+    </para>
+    <para>
+     <caution>
+      <para>
+       Do NOT unset the whole <varname>$_SESSION</varname> with
+       <literal>unset($_SESSION)</literal> as this will disable the
+       registering of session variables through the
+       <varname>$_SESSION</varname> superglobal.
+      </para>
+     </caution>
+    </para>
+    <para>
      <example>
       <title>
        Unregistering a variable with <link