Make SOP Amend Allocation screen only show lines that can be allocated

The SOP amend allocation screen allows selecting by customer, if you display on this basis it displays all item lines from live orders for the selected customer irrespective of if the item line can be allocated or it is complete. This makes the displayed data virtually useless as you have to select each item in turn to find what lines can be allocated. Can this be changed to display only products for lines that have yet to be allocated only.