public function setUpOnce() { if (!ShoppingCart_Controller::has_extension('ShoppingCartAjax')) { ShoppingCart_Controller::add_extension('ShoppingCartAjax'); } if (!VariationForm::has_extension('ShoppingCartAjax')) { VariationForm::add_extension('ShoppingCartAjax'); } if (!Controller::has_extension('AjaxControllerExtension')) { Controller::add_extension('AjaxControllerExtension'); } parent::setUpOnce(); }