You only need two listboxes for that. One for the client and one for the product. Select a client in the client listbox and you can see in the product list box which products the client bought (in white) and also the products the client didn't buy (in grey)
You only need two listboxes for that. One for the client and one for the product. Select a client in the client listbox and you can see in the product list box which products the client bought (in white) and also the products the client didn't buy (in grey)
