jquery mobile checkbox in popup not working

jquery mobile checkbox in popup not working. Clicking the checkbox could not change the checkbox value.

<div class="ui-popup-container pop in ui-popup-active" id="popup1-popup" >
<div id="popup1" data-role="popup" data-dismissible="false" data-theme="a" class="ui-popup ui-body-a ui-overlay-shadow ui-corner-all">

<div class=" ui-checkbox">
     <input type="checkbox" data-cacheval="false">
</div>

</div>
</div>

How to debug it? where to set a breakpoint? The style class ui-checkbox is added by enhancement, but the class ui-checkbox does not exist in jquery-mobile.js.

Thanks for help.