Due/Overdue - Shows all the rounds with Schedule Start Times that have past (Due) and all the rounds with Schedule Finish Times that have past (Overdue).
Today - Shows all the rounds that are scheduled to start in the current calendar day.
Tomorrow - Shows all the rounds that are scheduled to start in the next calendar day.
If your user profile has been assigned a particular shift structure, and there are operator rounds that have been scheduled according to the same shift structure, there are three additional filters available: Current Shift, Next Shift, and Previous Shift.