JSF-AJAX请求不能与hx:panelDialog一起使用

我写了以下代码,

        <h:form id="PrefForm" >
        <hx:commandExButton id="preferenceButton" type="button" style="align:right;" value="#{nls.preferenceLink }" title="#{nls.preferenceLinkTitle}" >
                    <hx:behavior event="onclick" behaviorAction="get" targetAction="prefPanelGroup"></hx:behavior>
                    <hx:behavior event="onclick" behaviorAction="show;stop" targetAction="preferenceSet"></hx:behavior>
        </hx:commandExButton>

        <hx:panelDialog id="preferenceSet"    type="modal" styleClass="panelDialog" title="#{nls.preferenceDialogTitle}" >
            <h:outputText styleClass="panelStartMessage" style="display:block;" value="#{nls.preferenceDialogWindowText}" />

            <h:panelGroup id="prefPanelGroup" rendered="#{neoReport.hasSelectItem }" style="display:block;width:300px;height:360px;overflow:auto;" >
                <hx:ajaxRefreshRequest id="refreshform" />
                <h:selectManyCheckbox value="#{neoReport.selectedItems}" layout="pageDirection">
                        <f:selectItems value="#{neoReport.selectItems}" />
                </h:selectManyCheckbox>
            </h:panelGroup> 

            <hx:panelBox id="noCommandWindow" rendered="#{!neoReport.hasSelectItem }" style="display:block;width:300px;height:50px;" layout="lineDirection"> 
                <h:outputText styleClass="outputText" id="cmdInfo"    value="#{nls.noCommands}" />
            </hx:panelBox>

            <h:panelGroup id="buttonBox1" styleClass="panelStartBox" >
                    <hx:commandExButton id="submitPref"    styleClass="commandExButton" type="submit" value="#{nls.submit}" action="#{neoReport.action}">
                        <hx:behavior event="onclick" behaviorAction="hide"    targetAction="preferenceSet" id="behaviorSubmitPref" />
                    </hx:commandExButton>
                    <hx:commandExButton id="CancelPref"    styleClass="commandExButton" type="submit" value="#{nls.cancel}" action="neoReport">
                        <hx:behavior event="onclick" behaviorAction="hide"    targetAction="preferenceSet" id="behaviorCancelPref" />
                    </hx:commandExButton>
            </h:panelGroup>
         </hx:panelDialog>
    </h:form>

<f:selectItems value="#{neoReport.selectItems}"

但它不会呈现panelDialog进一步。如果我删除了“get”的行为,它将显示面板对话框,但不会显示更新的数据。所以我不知道我到底做错了什么给你。我可以吗有人帮忙吗?