diff --git a/openerp/addons/base/ir/workflow/workflow_view.xml b/openerp/addons/base/ir/workflow/workflow_view.xml
index 44dbc54c718..d174928556f 100644
--- a/openerp/addons/base/ir/workflow/workflow_view.xml
+++ b/openerp/addons/base/ir/workflow/workflow_view.xml
@@ -52,6 +52,7 @@
             <field name="act_to"/>
             <field name="signal"/>
           </arrow>
+          <label string="When customizing a workflow, be sure you do not modify an existing node or arrow, but rather add new nodes or arrows. If you absolutly need to modify a node or arrow, you can only change fields that are empty or set to the default value. If you don't do that, your customization will be overwrited at the next update or upgrade to a future version of OpenERP."/>
         </diagram>
       </field>
     </record>
diff --git a/openerp/addons/base/rng/view.rng b/openerp/addons/base/rng/view.rng
index c583040495b..0d6527e5972 100644
--- a/openerp/addons/base/rng/view.rng
+++ b/openerp/addons/base/rng/view.rng
@@ -181,9 +181,12 @@
 
     <rng:define name="diagram">
         <rng:element name="diagram">
-            <rng:optional><rng:attribute name="string"/></rng:optional>
+            <rng:optional><rng:attribute name="string"/></rng:optional>                                    
             <rng:ref name="node"/>
-            <rng:ref name="arrow"/>
+            <rng:ref name="arrow"/>            
+            <rng:zeroOrMore>
+                <rng:ref name="label"/>
+            </rng:zeroOrMore>
         </rng:element>
     </rng:define>