Hi Aim,
Thanks for your response.
The same issue is happening here:
http://demo.x-cart.com/demo_goldplus/admin/order.php?orderid=1023
1) Add a tracking code
2) Refresh page so tracking button appears
3) Click tracking button
Normal result: New page opens with the tracking website
Current result: No new page opens, but the Track It! button acts as the Apply Changes button (it saves changes to the page, instead of actually tracking the order)