fullcalendar selectHelper is hidden on resize to restricted zone - fullcalendar

Question

the default behavor of selecthelper when resizing to a restricted zone(selectConstraint) is to hide the selectHelper, i want this to be exactly as event resize to a restricted zone(eventConstraint), where the event is visible and the size is the last allowed size.
this is the demo
http://jsfiddle.net/pu83thf9/3/
1)try to select from 10am to 2pm the selectHelper is hidden out of selectConstraint
2)try to create an event from 8-to 10 , try to resize it to 12 and don't release the mouse for 2 seconds, try now to resize it to 2pm, it's visible and not hidden like case 1
$(document).ready(function() {
$('#calendar').fullCalendar({
header: {
left: 'prev,next today',
center: 'title',
right: 'month,agendaWeek,agendaDay'
},
locale:"en",
minTime: "06:00:00",
maxTime: "20:00:00",
allDaySlot: false,
businessHours: true,
businessHours: [{
dow: [1, 2, 3, 4, 5], // Monday - Friday
start: '08:00',
end: '12:00',
}, {
dow: [1, 2, 3, 4, 5], // Monday - Friday (if adding lunch hours)
start: '13:00',
end: '17:00',
}],
selectConstraint: "businessHours",
eventConstraint: "businessHours",
defaultView: 'agendaWeek',
defaultDate: '2018-03-12',
navLinks: true, // can click day/week names to navigate views
selectable: true,
selectHelper: true,
select: function(start, end) {
var title = 'Zone';
var eventData;
if (title) {
eventData = {
title: title,
start: start,
end: end
};
$('#calendar').fullCalendar('renderEvent', eventData, true); // stick? = true
}
$('#calendar').fullCalendar('unselect');
},
editable: true,
eventOverlap :false,
selectOverlap :false,
eventLimit: true, // allow "more" link when too many events
eventRender: function (event, element, view) {
element.find(".closeon").on('click', function () {
$('#calendar').fullCalendar('removeEvents', event._id);
});}
});
});