/**
* Disable fields depending on product type
*
* @return Mage_CatalogInventory_Block_Adminhtml_Form_Field_Stock
*/
protected function _disableFields()
{
if (!$this->_isProductComposite() && null === $this->_qty->getValue()) {
$this->setDisabled('disabled');
}
if ($this->_isProductComposite()) {
$this->_qty->setDisabled('disabled');
}
return $this;
}
