Ajax Popup On New Checkout Page Problem

Hi i want show an confirmation pupup before place order at new checkout ( v4.10.x lite checkout )

check the checkout forum :

 

its not cm-ajax form.

i try checkout.pre with $mode == 'place_order'

with following code:

if (defined('AJAX_REQUEST')) {
        Tygh::$app['view']->assign([
            'return_url' => isset($_REQUEST['return_url']) ? $_REQUEST['return_url'] : null,
            'redirect_url' => isset($_REQUEST['redirect_url']) ? $_REQUEST['redirect_url'] : null,
            'title' => __('confirm_before_order'),
        ]);

        Tygh::$app['view']->display('addons/my_changes/components/confirm.tpl');
        exit;
    }

also i try wihout if (defined('AJAX_REQUEST'))

its show just when checkout complete with new page.

anyone can give suggest or hot fix this ?

Yes i have popup in checkout like this problem anyone know that solution??