The Working day is used to calculate how many hours constitude a day of leave or sickness.  This is closely tied to the work pattern in use by an employee.  As such we have moved the Working day setting to the work pattern pages.  Now when you add a new work pattern, you will also set its Working day and it will calculate how many days of leave will be booked for each day.  This will provide clearer information from setup and ensure that the Working Day and Work Pattern remain accurate.