I am trying to do some validations within a modal panel:

<rich:modalPanel id="addHt" autosized="true" width="450">

 <h:form id="frmMaintainHs">
 <rich:messages></rich:messages>
 <h:panelGrid id="pnlHs" columns="4"
 columnClasses="textLabel,list-left,textLabel,list-left">

 <h:panelGroup>
 <h:outputText value="#{msgs.Provider}:" styleClass="textLabel" />
 <span class="required">*</span>
 </h:panelGroup>

 <h:panelGroup>
 <h:selectOneMenu id="refProviders"
 value="#{hBean.selectedProvider}" required="true"
 requiredMessage="#{msgs.SelectValue}">
 <f:selectItems value="#{hBean.refernceProviderOptions}" />
 </h:selectOneMenu>
 <rich:message for="refProviders"></rich:message>
 </h:panelGroup>

 <a4j:commandButton id="submitQuery" value="Save"
 reRender="tblHts" action="#{hBean.updateHt}"
 oncomplete="if (#{facesContext.maximumSeverity==null}) #{rich:component('addHts')}.hide();"
 rendered="true">

 </a4j:commandButton>

 </h:panelGrid>
 </h:form>
 </rich:modalPanel>