<?php $form=$this->beginWidget('CActiveForm', array(
	'id'=>'plc-order-form',
	'enableAjaxValidation'=>false,
)); ?>
	<?php echo $form->errorSummary($model);
	    $tab1 = $this->renderPartial('_testata', array('model'=>$model,'form'=>$form), true);
        $tab2 = $this->renderPartial('_riga', array('modelP'=>$modelP,'modelOD'=>$modelOD,'form'=>$form,
        'categories'=>$categories,'category_id'=>$category_id), true);        
	?>
    <table width="100%" cellspacing="0" cellpadding="0" border="0">
<tbody>
<tr>
<td class="ip_cpanel_display" width="80%" valign="top">
	<?php $this->widget('zii.widgets.jui.CJuiTabs', array(
                'tabs'=>array(
                   'Testata ordine' =>array('content'=>$tab1),
                   'Articolo' =>array('content'=>$tab2),
	             
                ),
                    'options'=>array(
                        'collapsible'=>true,
                ),
        ));
        ?>
</td>
</tbody>
</table>       
  
	<?php $this->endWidget(); ?>
and the _partial view that action ajax post:
<div class="row">
		<?php echo $form->labelEx($modelP,'group_size_id'); ?>
			<?php echo $form->dropDownList($modelP, 'group_size_id', CHtml::listData(
                 XXXGroupSize::model()->findAll(), 'group_size_id', 'description'),array(
                        'prompt'=>'Seleziona un gruppo taglia:',
						'ajax' => array(
                        'data'=>'js:jQuery("#XXXProduct_group_size_id").serialize()',
						'type'=>'POST',
						'url'=>CController::createUrl('XXXProduct/groupSize'),
						'update'=>'#varianti',
                 						
						))); ?>
	</div>	
			<div class="row">
		<?php echo $form->labelEx($modelP,'wholesale_price'); ?>
		<?php echo $form->textField($modelP,'wholesale_price',array('size'=>15,'maxlength'=>15)); ?>
		<?php echo $form->error($modelP,'wholesale_price'); ?>
	</div>
	<div class="row">
		<?php echo $form->labelEx($modelP,'price'); ?>
		<?php echo $form->textField($modelP,'price',array('size'=>15,'maxlength'=>15)); ?>
		<?php echo $form->error($modelP,'price'); ?>
	</div>
	
	<div class="row">
		<?php echo $form->labelEx($modelP,'discount'); ?>
		<?php echo $form->textField($modelP,'discount'); ?>
		<?php echo $form->error($modelP,'discount'); ?>
	</div>
	<div class="row">
		<?php echo $form->labelEx($modelP,'markup'); ?>
		<?php echo $form->textField($modelP,'markup'); ?>
		<?php echo $form->error($modelP,'markup'); ?>
	</div>
	<div class="row">
		<?php echo $form->labelEx($modelP,'tax_class_id'); ?>
			<?php echo $form->dropDownList($modelP, 'tax_class_id', CHtml::listData(
                 PlcTaxClass::model()->findAll(), 'tax_class_id', 'rate'));?>
	</div>
		<div id ="varianti">
	<?php if(isset($modelP->product_id)){
	echo $this->renderPartial('_variazione', array('model'=>$modelP,'taglia'=>$taglia));
	}?>
</div>
that’s all…
thnks