I've got a page with this piece of xhtml in:
<f:subview> <h:panelGroup id="findJobPanel"> <a4j:include viewId="/findJob/search.xhtml"/> </h:panelGroup> </f:subview>
<h:message for="jobNumber" styleClass="cntError"/>
facesMessages.addToControl("jobNumber", "Job number #{jobNumber} not found");
as described in ajax4jsf documentation you must use a4j:outputPanel with ajaxRendered="true" as wrapper for your messages. Did you perform that?