Color an entire day instead of single event in calendar plugin

Good day guys! Is there a way I can mark/color an entire day in the full calendar plug-in? I’m guessing it has something to do with the all day field (screenshot below), but I read the documentation and tried it out but it didn’t work for me.

Basically what I’m trying to do is, when the calendar detects an event that I set in the database as a “whole day event”, I want it to color the entire day in the calendar under month view, not just a single line like the one here:

My use case is actually something like, a doctor marking that day as a day where he/she won’t be working the entire day at all, so that day becomes out of the question when scheduling an appointment.