Tiles2 error with cascade attribute in put-attribute tag

I just don't know why i get this error:

2010-10-28 16:32:29,925 ERROR [ache.commons.digester.Digester.error          :1635] - Parse Error at line 45 column 56: Attribute "cascade" must be declared for element type "put-attribute".
org.xml.sax.SAXParseException: Attribute "cascade" must be declared for element type "put-attribute".

tiles.xml looks something like this (only relevant parts):

<tiles-definitions>
<definition name="customerBaseLayout" template="/pages/customer/templates/baseLayout.jsp">
    <put-attribute name="title" value="Pannello Operatore"/>
    <put-attribute name="header" value="/pages/customer/templates/header.jsp"/>
    <put-attribute name="footer" value="/pages/customer/templates/footer.jsp"/>
</definition>
<definition name="userBaseLayout" extends="customerBaseLayout">
    <put-attribute name="header" value="/pages/guest/templates/user/header.jsp"/>

    <put-attribute name="sidebar" cascade="true" />
</definition>

I did try setting the value attribute too but no use. The cascade attr I found in the documentation here

I am using netBeans 6.9 with struts 2.1 and tiles 2.0.6 The ide does not know about the cascade attribute in code hints.

Solution

You're using Tiles 2.0.6 but "cascade" is only in the 2.1 DTD.