i’ve same problem with you that i cannot update ajax dropDownList, and also the datejui that not work…
3 days to find out 
this is caused by the ID for the FORM at _ajax_form.php and the ID of FORM at Search form have same name
ex: my ajax_form id Mareal_kabupaten, and at search input ID also Mareal_kabupaten
then when ajax or datejui update the form identify the ID Mareal_kabupaten then ajax or datejui update the first ID found, the first ID was at search FORM, then it’s funny that input form have option 
solution: try to remark everything about SEARCH form
in my case : i just remark this at index.php
<?php
/*Yii::app()->clientScript->registerScript(‘search’, "
$(’.search-button’).click(function(){
$('.search-form').toggle();
return false;
});
$(’.search-form form’).submit(function(){
$.fn.yiiGridView.update('mareal-grid', {
data: $(this).serialize()
});
return false;
});
");*/
?>
<h1>Mareals </h1>
<?php /*?> <p class="left">You may optionally enter a comparison operator (<b><</b>, <b><=</b>, <b>></b>, <b>>=</b>, <b><></b>
or <b>=</b>) at the beginning of each of your search values to specify how the comparison should be done.</p><?php echo CHtml::link(‘Advanced Search’,’#’,array(‘class’=>‘search-button’)); ?><div class=“search-form” style=“display:none”>
<?php $this->renderPartial(’_search’,array(
'model'=>$model,
)); ?>
</div><!-- search-form --><?php */?>
i just remark all search form and… ALL WORKS… I AM VERRY HAPPY… 3 days working with good result 
and for you drumaddict who create this ajaxgiicrud… you are the best… made my work eazy with your one page form:)