Problem with fullCalendar : today's day disappears - html

Question

i have a problem with fullcalendar. i don't know why but when i reload my page, i wait 2 seconds and today's day disappears and the line is shifting.
I do not know where the problem may come from.
Tanks a lot for your help
Edit: sorry for not having put code.
I thought it might be a classic problem that many had. Sorry again
Here is my code :
<!-- language: lang-js -->
document.addEventListener('DOMContentLoaded', function () {
var events = <?php echo json_encode($events) ?>;
var date = new Date();
var d = date.getDate(),
m = date.getMonth(),
y = date.getFullYear();
var calendarEl = document.getElementById('calendar');
var calendar = new FullCalendar.Calendar(calendarEl, {
locale: 'fr',
plugins: ['interaction', 'dayGrid', 'list', 'googleCalendar', 'bootstrap', 'moment'],
themeSystem: 'bootstrap',
header: {
left: 'prev,next today',
center: 'title',
right: 'dayGridMonth,listYear'
},
navLinks: true,
selectable: true,
selectMirror: true,
select: function (arg) {
var start = moment(arg.start).format('YYYY/MM/DD HH:mm:ss');
console.log(start);
$("#date").val(start);
$('#addModal').modal();
if ($('#addModal').modal()) {
calendar.addEvent({
start: arg.start,
end: arg.end,
allDay: arg.allDay
});
$.ajax({
url: '<?= base_url(); ?>index.php/Admin/add_event',
data: {start: arg.start, end: arg.end},
type: "POST",
success: function (response) {
displayMessage("Updated Successfully");
}
});
}
calendar.unselect();
},
editable: true,
eventLimit: true,
displayEventTime: false,
events: events
});
calendar.render();
});
a screen capture

Answer 1

The problem is solved.
I found that it had a conflict between my bootstrap file and my js file where I had a :
window.setTimeout (function () {
$ (". alert"). slideUp (500, function () {
$ (This) .remove ();
});
}, 2000);
I think there was a class "alert" on the current day
Thanks a lot to ADyson