brendan.feltrupexum PRO said over 2 years ago on FullCalendar with StimulusJS :
For those wanting to make the box selectable and the date number zoom to the daily grid this is my edits: 

selectable: true,

navLinkDayClick: function(date, jsEvent) {
        calendar.changeView('timeGridDay', date);
        },

    
      select: function(info) {
        _this.modalTarget.style.display = "block"
        _this.start_timeTarget.value = info.start
        _this.end_timeTarget.value = info.end
        },

I added the selectable to the options and added the select function with the modal part and changed the naveLinkDayClick to the changeView