JSF ajax从下拉列表重新加载整个页面

<h:selectOneMenu id="dropdownDevice"
        value="#{skinningBean.currentDevice}" converter="SkinConverter">
        <f:selectItems value="#{skinningBean.myDevicesSI}" var="c"
            itemValue="#{c}" />
        <f:ajax event="change" render="preview" />
</h:selectOneMenu>
<h:selectOneMenu id="dropdownDevice"
        va