I'm using rich:combobox and a4j:support components to filter values from datatable column. It works fine on firts call (rich:datatable is rendered and data from column are filtered) but after rerenderig I can not filter again because the page show a Javascript error "Invalid Argument"
This is my code:

<ui:composition xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:a4j="http://richfaces.org/a4j"
xmlns:rich="http://richfaces.org/rich">
<ui:define name="body">
<a4j:form>

<rich:dataTable
width="700" border="0" var="org" value="#{LableBean.datamodel}" id="labelList">

<f:facet name="header">
<rich:columnGroup>
<rich:column >
Column1
</rich:column>
..........
</rich:columnGroup>
</f:facet>

<rich:column >
<f:facet name="header">
<rich:combobox value="#{LableBean.ComboFilter}" id="comboId" >
<a4j:support event="onkeyup" rerender="labelList" actionListener="#{LableBean.filterAction}" ignoredumpresponse="true" >
<f:param name="filterfolder" value="combo"/>
</a4j:support>
</rich:combobox>
</f:facet>
<f:outputText value="#{org.combo}"/>
</rich:column>
.............
</rich:dataTable>
</a4j:form>
</ui:define>
</ui:composition>
I don't know if I'm duing somethig wrong or It is a richfaces bug.