使用选项列表时，JSF2 CommandButton无法正常工作

Question

我正在使用包含primefaces选项列表的表单。当我点击commandButton时没有任何反应。如果我删除了pickList，它可以正常工作。

<ui:define name="content">
<h:form>
    <div class="form">
        <p:panel id="panel" header="#{msgs['group.message.create']}">

            <p:messages id="msgs" display="icon" />

            <h:panelGrid columns="3">

                <h:outputLabel for="name" value="#{msgs['general.text.name']} *" />
                <h:outputText value="#{groupBean.group.name}" rendered="#{groupBean.group.id != null and groupBean.group.id != 0}" />
                <p:inputText required="true" id="name" value="#{groupBean.group.name}" label="#{msgs['general.text.name']}"
                    rendered="#{groupBean.group.id == null or groupBean.group.id == 0}"/>
                <p:message for="name" display="icon" />

                <h:outputLabel for="description" value="#{msgs['general.text.description']} *" />
                <p:inputTextarea required="true" id="description" value="#{groupBean.group.description}" label="#{msgs['general.text.description']}"/>
                <p:message for="description" display="icon" />

                <h:outputLabel for="pickList" value="#{msgs['group.message.permissions']} *" />
                <p:pickList required="true" id="pickList" value="#{groupBean.permissions}" label="#{msgs['group.message.permissions']}"
                        var="p" itemLabel="#{p.description}" itemValue="#{p}" converter="permissionConverter"/>
                <br/>
                </h:panelGrid>


            <div class="buttons">
                <h:commandButton id="save" value="#{msgs['common.saveButton']}" action="#{groupBean.saveGroup}" styleClass="redButton" />
                <h:commandButton class="greyButton" id="cancel" value="#{msgs['general.text.cancel']}" action="listGroups.xhtml?faces-redirect=true" immediate="true" />
            </div>
        </p:panel>
        <h:inputHidden id="groupId" value="#{groupBean.group.id}" />
    </div>
</h:form>