Force select a variation

Hi there

How can we make sure that for every variable product a variation is selected (force select variation)?

We are using this code which is working perfectly for the products that are visible BEFORE infinite scrolling / reload. So it looks like this is not compatible with YITH infinite scrolling plugin.

add_filter(‘woocommerce_dropdown_variation_attribute_options_args’,’fun_select_default_option’,10,1);
function fun_select_default_option( $args)
{

if(count($args['options']) > 0) //Check the count of available options in dropdown
    $args['selected'] = $args['options'][0];
return $args;

}

Thanks for your help!