Sales of negative inventory

Hi Ateeq,

I observed that is it is possible to still sell products even though the inventory is negative.

Please i need this bloscked. TI should not be possible to see when inventory is negative. Infact i think inventory should never even get to negative.

Please i need your urgent response. 

We built this system for retail shops where customers select products from shelves and then cashier scan them to enter in system and sell them. So this gives assurity only products are being sold which are available in store. We did not stop products from selling when they are below 0 because many systems want to sell them while they are 0 as they have stock in process.