1) Insert next code into source path
<m:message xmlns="http://www.w3.org/1999/xhtml"
xmlns:m="http://jboss.com/products/seam/mail"
xmlns:h="http://java.sun.com/jsf/html">

<m:from name="Peter" address="yzhishko@exadel.com" />
<m:to name="Yura Zhishko">yzhishko@mail.ru</m:to>
<m:subject>Try out Seam!</m:subject>
<m:attachment/>

<m:body>
<p style="color:red"><h:outputText value="Dear Yura" />,</p>
<p style="color:green">You can try out Seam by visiting
<a href="http://labs.jboss.com/jbossseam">http://labs.jboss.com/jbossseam</a>.</p>
<p>Regards,</p>
<p>Pete</p>
</m:body>

</m:message>
2) Select any tag, and try to add attribute using CA
RESULT: There are no CA proposals for attributes.