The barcode reader I own enters new line at the end of the barcode (code 13) and if the mouse pointer is above a button it will press it before adding the product. For example I put with the mouse product 1 and then if I scan product 2 I end up with 2 x product 1 and 1x product 2 (the mouse is still over product 1). To avoid I have to make sure that the mouse pointer is on the empty area before scanning a product. This doens't happen if I use barcode scanner which doesn´t put new line at the end.

How can I fix that?