Sales Orders 'List' tab:  What is the 'Customise' button used for?

In the Sales Orders 'List' tab there is a 'Customise' button at the bottom-right corner.  This button isn't truly functional.  It's a left-over button from the past that we've yet to remove.  It hasn't been removed because the programming code between the Quotes, Sales Orders and Jobs modules are very intertwined and programming changes made to the opening 'List' tab for any of those usually has an interesting, yet unintentional, effect on the others.  So, until we've separated that code out more (as well as developed separate database tables for each of those), the 'Customise' button has to be left there.