I have recently been having problems with Magento's one page checkout system.
At the moment it is working in a basic way, but the progress steps which are normally displayed on the right hand side are not being updated when the steps are completed. The step headings are showing up (Billing Address, Shipping Address, etc.), and I can control their styles through the boxes.css settings, but they don't get filled in with the content as the customer step through the process.
I have tried a number of solutions, including:
changing the xml and tweaking the opchecout.js file
What is the best way to debug something like this?