A simple way to check if all sales orders are invoiced

[joebordes]

What I usually do for this use case is add a button to the list view (your ideas is along the right path :-) ). That way the user can use all the filtering conditions and or search facilities the application gives you, which the user already knows how to use, the user then selects the SO he wants to check and the button goes off to another script which receives the list of selected records and does the magic it has to do.

HTH