primefaces - Primefaces p:confirmDialog 动作监听器如果进程不指向表单 id 则不会触发

Question

    <p:selectOneMenu id="country" value="#{empCon.selectedCountry}" required="true" onchange="PF('confirm').show()">
        <f:selectItem itemLabel="-SELECT-" itemValue="NULL" noSelectionOption="true"></f:selectItem>
        <f:selectItems value="#{empCon.country}" 
                                var="a"
                                itemLabel="#{a}"
                                itemValue="#{a}"></f:selectItems>
    </p:selectOneMenu> <p:confirmDialog widgetVar="confirm" appendToBody="false" message="Are you sure you want to change your selection?" header="Confim" severity="alert">
<h:form>
<p:commandButton value="Yes" process=":te:country" update=":te:province :te:messages" 
actionListener="#{empCon.onSelectCountry}"
oncomplete="PF('confirm').hide()" />
<p:commandButton value="No" type="button"  onclick="PF('confirm').hide()" />
    </h:form>   

使用此代码不会触发“onSelectCountry”actionListener。但是，如果我将进程属性的值更新为仅表单 id(":te") 它可以工作。请回答; 我只想知道根本原因。