Difficulties Asp.NET MVC ... window does not appear correctly

I'm new to the ASP.NET MVC world and I've had some initial difficulties. I am trying to develop a calendar but clicking on a day to make an event ... the window appears in a strange way, does anyone know the reason?

Images with the error

IfyouopenInspectionandmoveittotheleft...toacertainposition...italreadyshowscorrectlyasitisinthelinkimagebelow

Controller

usingSystem.Linq;usingSystem.Web.Mvc;usingWebApplication.Models.BaseDados;namespaceWebApplication.Controllers{publicclassCalendarController:Controller{publicActionResultIndex(){returnView();}publicJsonResultGetEvents(){using(HotelEntitiesdc=newHotelEntities()){varevents=dc.Events.ToList();returnnewJsonResult{Data=events,JsonRequestBehavior=JsonRequestBehavior.AllowGet};}}[HttpPost]publicJsonResultSaveEvent(Eventse){varstatus=false;using(HotelEntitiesdc=newHotelEntities()){if(e.EventID>0){//Updatetheeventvarv=dc.Events.Where(a=>a.EventID==e.EventID).FirstOrDefault();if(v!=null){v.Subject=e.Subject;v.Start=e.Start;v.End=e.End;v.Description=e.Description;v.IsFullDay=e.IsFullDay;v.ThemeColor=e.ThemeColor;}}else{dc.Events.Add(e);}dc.SaveChanges();status=true;}returnnewJsonResult{Data=new{status=status}};}[HttpPost]publicJsonResultDeleteEvent(inteventID){varstatus=false;using(HotelEntitiesdc=newHotelEntities()){varv=dc.Events.Where(a=>a.EventID==eventID).FirstOrDefault();if(v!=null){dc.Events.Remove(v);dc.SaveChanges();status=true;}}returnnewJsonResult{Data=new{status=status}};}}}

Index

@{ViewBag.Title="Calendar";
    ViewBag.SubTitle = "";
}

<div id="calender"></div>

<div id="myModal" class="modal fade" role="dialog">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal">&times;</button>
                <h4 class="modal-title"><span id="eventTitle"></span></h4>
            </div>
            <div class="modal-body">
                <button id="btnDelete" class="btn btn-default btn-sm pull-right">
                    <span class="glyphicon glyphicon-remove"></span> Remove
                </button>
                <button id="btnEdit" class="btn btn-default btn-sm pull-right" style="margin-right:5px;">
                    <span class="glyphicon glyphicon-pencil"></span> Edit
                </button>
                <p id="pDetails"></p>
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
            </div>
        </div>
    </div>
</div>

<div id="myModalSave" class="modal fade" role="dialog">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal">&times;</button>
                <h4 class="modal-title">Save Event</h4>
            </div>
            <div class="modal-body">
                <form class="col-md-12 form-horizontal">
                    <input type="hidden" id="hdEventID" value="0" />
                    <div class="form-group">
                        <label>Subject</label>
                        <input type="text" id="txtSubject" class="form-control" />
                    </div>
                    <div class="form-group">
                        <label>Start</label>
                        <div class="input-group date" id="dtp1">
                            <input type="text" id="txtStart" class="form-control" />
                            <span class="input-group-addon">
                                <span class="glyphicon glyphicon-calendar"></span>
                            </span>
                        </div>
                    </div>
                    <div class="form-group">
                        <div class="checkbox">
                            <label><input type="checkbox" id="chkIsFullDay" checked="checked" />  Is Full Day event</label>
                        </div>
                    </div>
                    <div class="form-group" id="divEndDate" style="display:none">
                        <label>End</label>
                        <div class="input-group date" id="dtp2">
                            <input type="text" id="txtEnd" class="form-control" />
                            <span class="input-group-addon">
                                <span class="glyphicon glyphicon-calendar"></span>
                            </span>
                        </div>
                    </div>
                    <div class="form-group">
                        <label>Description</label>
                        <textarea id="txtDescription" rows="3" class="form-control"></textarea>
                    </div>
                    <div class="form-group">
                        <label>Theme Color</label>
                        <select id="ddThemeColor" class="form-control">
                            <option value="">Default</option>
                            <option value="red">Red</option>
                            <option value="blue">Blue</option>
                            <option value="black">Black</option>
                            <option value="green">Green</option>
                        </select>
                    </div>
                    <button type="button" id="btnSave" class="btn btn-success">Save</button>
                    <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                </form>
            </div>
        </div>
    </div>
</div>

<link href="~/AdminLTE/bootstrap/css/bootstrap.min.css" rel="stylesheet" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script><scriptsrc="~/AdminLTE/bootstrap/js/bootstrap.min.js"></script>
<link href="~/AdminLTE/plugins/fullcalendar-3.9.0/fullcalendar.min.css" rel="stylesheet" />
<link href="~/AdminLTE/plugins/fullcalendar-3.9.0/fullcalendar.print.min.css" rel="stylesheet" media="print" />
<link href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datetimepicker/4.17.47/css/bootstrap-datetimepicker.min.css" rel="stylesheet" />
@section Scripts{
    <script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.18.1/moment.min.js"></script><scriptsrc="~/AdminLTE/plugins/fullcalendar-3.9.0/fullcalendar.min.js"></script>
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datetimepicker/4.17.47/js/bootstrap-datetimepicker.min.js"></script><script>$(document).ready(function(){varevents=[];varselectedEvent=null;FetchEventAndRenderCalendar();functionFetchEventAndRenderCalendar(){events=[];$.ajax({type:"GET",
                    url: "/calendar/GetEvents",
                    success: function (data) {
                        $.each(data, function (i, v) {
                            events.push({
                                eventID: v.EventID,
                                title: v.Subject,
                                description: v.Description,
                                start: moment(v.Start),
                                end: v.End != null ? moment(v.End) : null,
                                color: v.ThemeColor,
                                allDay: v.IsFullDay
                            });
                        })

                        GenerateCalender(events);
                    },
                    error: function (error) {
                        alert('failed');
                    }
                })
            }

            function GenerateCalender(events) {
                $('#calender').fullCalendar('destroy');
                $('#calender').fullCalendar({
                    contentHeight: 400,
                    defaultDate: new Date(),
                    timeFormat: 'h(:mm)a',
                    header: {
                        left: 'prev,next today',
                        center: 'title',
                        right: 'month,basicWeek,basicDay,agenda'
                    },
                    eventLimit: true,
                    eventColor: '#378006',
                    events: events,
                    eventClick: function (calEvent, jsEvent, view) {
                        selectedEvent = calEvent;
                        $('#myModal #eventTitle').text(calEvent.title);
                        var $description = $('<div/>');
                        $description.append($('<p/>').html('<b>Start:</b>' + calEvent.start.format("DD-MMM-YYYY HH:mm a")));
                        if (calEvent.end != null) {
                            $description.append($('<p/>').html('<b>End:</b>' + calEvent.end.format("DD-MMM-YYYY HH:mm a")));
                        }
                        $description.append($('<p/>').html('<b>Description:</b>' + calEvent.description));
                        $('#myModal #pDetails').empty().html($description);

                        $('#myModal').modal();
                    },
                    selectable: true,
                    select: function (start, end) {
                        selectedEvent = {
                            eventID: 0,
                            title: '',
                            description: '',
                            start: start,
                            end: end,
                            allDay: false,
                            color: ''
                        };
                        openAddEditForm();
                        $('#calendar').fullCalendar('unselect');
                    },
                    editable: true,
                    eventDrop: function (event) {
                        var data = {
                            EventID: event.eventID,
                            Subject: event.title,
                            Start: event.start.format('DD/MM/YYYY HH:mm A'),
                            End: event.end != null ? event.end.format('DD/MM/YYYY HH:mm A') : null,
                            Description: event.description,
                            ThemeColor: event.color,
                            IsFullDay: event.allDay
                        };
                        SaveEvent(data);
                    }
                })
            }

            $('#btnEdit').click(function () {
                //Open modal dialog for edit event
                openAddEditForm();
            })
            $('#btnDelete').click(function () {
                if (selectedEvent != null && confirm('Are you sure?')) {
                    $.ajax({
                        type: "POST",
                        url: '/calendar/DeleteEvent',
                        data: { 'eventID': selectedEvent.eventID },
                        success: function (data) {
                            if (data.status) {
                                //Refresh the calender
                                FetchEventAndRenderCalendar();
                                $('#myModal').modal('hide');
                            }
                        },
                        error: function () {
                            alert('Failed');
                        }
                    })
                }
            })

            $('#dtp1,#dtp2').datetimepicker({
                format: 'DD/MM/YYYY HH:mm A'
            });

            $('#chkIsFullDay').change(function () {
                if ($(this).is(':checked')) {
                    $('#divEndDate').hide();
                }
                else {
                    $('#divEndDate').show();
                }
            });

            function openAddEditForm() {
                if (selectedEvent != null) {
                    $('#hdEventID').val(selectedEvent.eventID);
                    $('#txtSubject').val(selectedEvent.title);
                    $('#txtStart').val(selectedEvent.start.format('DD/MM/YYYY HH:mm A'));
                    $('#chkIsFullDay').prop("checked", selectedEvent.allDay || false);
                    $('#chkIsFullDay').change();
                    $('#txtEnd').val(selectedEvent.end != null ? selectedEvent.end.format('DD/MM/YYYY HH:mm A') : '');
                    $('#txtDescription').val(selectedEvent.description);
                    $('#ddThemeColor').val(selectedEvent.color);
                }
                $('#myModal').modal('hide');
                $('#myModalSave').modal();
            }

            $('#btnSave').click(function () {
                //Validation/
                if ($('#txtSubject').val().trim() == "") {
                    alert('Subject required');
                    return;
                }
                if ($('#txtStart').val().trim() == "") {
                    alert('Start date required');
                    return;
                }
                if ($('#chkIsFullDay').is(':checked') == false && $('#txtEnd').val().trim() == "") {
                    alert('End date required');
                    return;
                }
                else {
                    var startDate = moment($('#txtStart').val(), "DD/MM/YYYY HH:mm A").toDate();
                    var endDate = moment($('#txtEnd').val(), "DD/MM/YYYY HH:mm A").toDate();
                    if (startDate > endDate) {
                        alert('Invalid end date');
                        return;
                    }
                }

                var data = {
                    EventID: $('#hdEventID').val(),
                    Subject: $('#txtSubject').val().trim(),
                    Start: $('#txtStart').val().trim(),
                    End: $('#chkIsFullDay').is(':checked') ? null : $('#txtEnd').val().trim(),
                    Description: $('#txtDescription').val(),
                    ThemeColor: $('#ddThemeColor').val(),
                    IsFullDay: $('#chkIsFullDay').is(':checked')
                }
                SaveEvent(data);
                // call function for submit data to the server
            })

            function SaveEvent(data) {
                $.ajax({
                    type: "POST",
                    url: '/calendar/SaveEvent',
                    data: data,
                    success: function (data) {
                        if (data.status) {
                            //Refresh the calender
                            FetchEventAndRenderCalendar();
                            $('#myModalSave').modal('hide');
                        }
                    },
                    error: function () {
                        alert('Failed');
                    }
                })
            }
        })
    </script>
}