Updating A Listbox According To The Record You're Viewing

Hi

I have a database containing 3 tables (for now):
Customers
Orders
Catagories

Now i also have a form with customer information.
In that form is a listbox with a query statement, so that should display wich orders are placed by that customer.

SELECT Orders.[Order-ID], Orders.Description, Orders.Date, Orders.Category FROM Orders WHERE Customer=[Customer-ID];


Now this works for the first costumer record being displayed.
However when i view the next costumer, the listbox still displays the order information from the first customer.

How can i get the listbox to update itself when a diffirent record is viewed?

Thanks in advance