Hi Andrew,
I believe that might be the issue - they are sitting on the "Previously opened" list - that is why I asked you to check with dev regarding the file handling as the solution would therefore be very simple - tell them not to do that!
Adding shortcuts to each set of books is a good idea but most users deal with between 3 to 5 sets of books across the different modules so it quickly becomes icon mania...
Thank you and,
Cheers, JK