I'm trying to disable specific hours range for selected date cell, but it does not working.
( args.cell.start === new DayPilot.Date("2020-12-02") && (args.cell.start.getHours() >= 7 && args.cell.start.getHours() < 15))
What is wrong in my condition?
The first condition is only true for the first cell in a day (which start at 00:00). You need to compare the date part instead:
args.cell.start.getDatePart() === new DayPilot.Date("2020-12-02").getDatePart()
args.cell.start.getHours() >= 7
args.cell.start.getHours() < 15