Launching the window can have many uses, one of which is to compare prior years schedules and the amounts that were entered in that schedule.
Launch a window
With one of the returns open, go to the schedule you want to compare and click on the Launch Current Window icon. This can also be done by going to Window and choosing Launch Current Window.
Then, go to the return and the schedule you are comparing and follow the same steps of launching the window. You can manually drag the windows side by side to organize the windows for comparison.