Inventory Problem On the Opencart

Hi all,

Can anyone help me to fix this prob with regards to the inventory of the open cart,
The logic of the inventory is that the stocks shall be reduced when an item has been checked out/shipped or when the item/transaction is completed.

And when the customer requests to cancel his/her transaction/order, the item/stocks on your inventory should be added.

lets say,

INVENTORY
STOCKS (Quantity)  5

when the customer cancelled his order, the number of quantity on your stocks should be 6 right?

but in the latest version I downloaded, when I shipped, cancelled an order (on the admin site) the quantity retains... it wont affect at all

what should i do? thanks for your feedback

Please don't double post.