You have to set XPages property
dojoParseOnLoad="true"
with setting the property "Trigger Dojo parse on load" at Dojo tab. Then you'll get a nice menu without a date time picker.
Date time picker causes setting this property automatically during rendering. You can see the property at rendered page here:
<script type="text/javascript" src="/xsp/.ibmxspres/dojoroot-1.6.1/dojo/dojo.js"
... parseOnLoad: true"></script>