<ui:define name="body">
	<f:verbatim>
		<a href="javascript:Richfaces.showModalPanel('_panel',{left:'auto', top:'auto'})">
			Show Modal Panel
		</a>
	</f:verbatim>
	<rich:modalPanel id="_panel">
		<f:facet name="header">
			<h:outputText value="test"></h:outputText>
		</f:facet>
		<h:form id="mpform">
			<a4j:outputPanel ajaxRendered="true">
				<h:messages id="error"></h:messages>
			</a4j:outputPanel>
			<h:inputText value="#{bean.property}" required="true"></h:inputText>
			<a4j:commandLink value="click" oncomplete="windowclose();"
				reRender="test" />
		</h:form>
	</rich:modalPanel>
	<script type="text/javascript">
		//<![CDATA[
			function windowclose(){
				if (document.getElementById('mpform:error')==null){
					Richfaces.hideModalPanel('_panel');
				};
			};
//]]>

	</script>
</ui:define>

All that we perform inside the panel - we check whether the messages are created on a page. And if the messages don't appear, just close the window. In the other case nothing is done, so the window stays with the messages inside.

See also solution #2

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