Php edit function overwrites instead of change existing record

public function editDeskdropItem($deskdropId = null){
$app = Wow_Application::getInstance();
$deskdropId = Wow_Utility::getGPValue('deskdropId');
$deskdrop = new Wow_Deskdrop_Model;
$deskdrop->load($deskdropId);
$html = Wow_Deskdrop_View_Admin::listMenu();
$html .= Wow_Deskdrop_View_Admin::deskDropForm($deskdrop);
$app->document->addHtmlToId('content', $html);
}