I have created a new calendar based in Islamic weekend (I set ONLY Friday as a non working day). When I apply the new calendar although it practically works, the Friday is the non working day, it does not reflected on the screen. Saturday and Sunday continue to be shaded as the non working days.
The background of the Gantt chart is usually the “Standard” calendar. Right click in the background of the Gantt chart (blank area_ and choose “Nonworking Time”. Select your new calendar as the calendar.