As you know, I've been trying to eliminate php undefined variable and undefined index notices during operation of the zxpos add-on. zxpos uses zen cart as a point of sale system does as much processing as possible in the browser, so ajax and jscripts are used extensively. The products we plan to sell with the point of sale system are mostly products with attributes, hence all the interaction with you and SBA. The error I've been chasing lately is an undefined index in shopping_cart.php in function in_cart_product_mixed_changed_shopping_cart which occurs when the product quantity is changed on the zxpos main page. The error is caused because the products_mixed_quantity field is set to 1. After setting the field to 0, the error goes away and everything seems to work properly. But the processing path taken for updating quantity on the zxpos main page is completely different from the path when the quantity is changed on the normal zen cart shopping cart page or on the product info page. There are no undefined index notices and in fact, function in_cart_product_mixed_changed_shopping_cart is not entered at all, at least for my products, even when products_mixed_quantity is set to 1 in the database.

At this point, I have eliminated the error I was chasing and can't afford to spend more time finding out why the path is the way it is for the point of sale add-on. Thanks again for all the help and advice, and for your support of SBA.

Dave