My customer like to leave the POS receipt screen on and he always forget to click [Next Order] but just scan a new barcode for the next order, as a result, it appends the scanned product into the previous order although the previous order had already issued a receipt. I think is a bug in odoo8

Is there a way  I can ignore barcode scan at Receipt screen, only allow [Print] [Next Order]?I have figure out some changes is required at screens.js  but need some help where to do the checking.