Also stay in the loop with what's going on through these awesome links:
Presently if you want to see all UNPAID invoices, you have to select unpaid, partial and past due. Lets define unpaid - any invoice with an amount greater than zero regardless of age. Partial - any invoice with an amount greater than zero BUT less than the original invoice amount. Past Due - any invoice with an amount greater than zero and older than XX days (where xx is determined by the user in a set-it and forget it fashion). When something is selected as a default setting, it should remain, including the number of invoices to be displayed.