diff --git a/reference/errorfunc/functions/set-error-handler.xml b/reference/errorfunc/functions/set-error-handler.xml
index 16ef16882e..73ee947ecc 100644
--- a/reference/errorfunc/functions/set-error-handler.xml
+++ b/reference/errorfunc/functions/set-error-handler.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.31 $ -->
+<!-- $Revision: 1.32 $ -->
 <!-- splitted from ./en/functions/errorfunc.xml, last change in rev 1.1 -->
 <refentry id="function.set-error-handler">
  <refnamediv>
@@ -128,6 +128,7 @@
            the error occurred.  In other words, <parameter>errcontext</parameter>
            will contain an array of every variable that existed in the scope the
            error was triggered in.
+           User error handler must not modify error context.
           </simpara>
          </listitem>
         </varlistentry>