When you start Totals it will display the client list by default. This is a design decision to make life easier for newcomers. The only mandatory object to create an invoice is a client. Therefore the client list is the first view that will be displayed when you open Totals.
If you don’t like it, you don’t have to be stuck with it. Totals displays the view of the first node in the source tree. Here is an example how Totals will display draft documents on startup.
You can even let display already sent invoices by default by dragging the the “Invoice” folder to the first place.