To reproduce: run the sample project and follow the illustrates steps from the gif file.

Workaround: close the tooltip programmatically:

        private void radScheduler1_AppointmentMouseDown(object sender, SchedulerAppointmentMouseEventArgs e)
        {
            if (tooltip != null)
            {
                tooltip.Hide(this.radScheduler1);
            }
        }

        ToolTip tooltip = null;

        private void radScheduler1_ToolTipTextNeeded(object sender, Telerik.WinControls.ToolTipTextNeededEventArgs e)
        {
            AppointmentElement app = sender as AppointmentElement;
            if (app != null)
            {
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < 10; i++)
                {
                    sb.AppendLine(app.Appointment.Summary + i + " " + app.Appointment.Summary + i + i + " " + app.Appointment.Summary);
                }
                e.ToolTipText = sb.ToString();
                tooltip = e.ToolTip;
            }
        }

If you want to show the borders for the weekdays, the left most border is not shown because another element is over the cell. It is not possible to hide this top left cell and show the left border for Sunday.

This is reproducible not only with Material theme but with the other themes as well.

Workaround:

        private void radScheduler1_CellFormatting(object sender, Telerik.WinControls.UI.SchedulerCellEventArgs e)
        {
            e.CellElement.ZIndex = 0;
        }

Run the application on a Windows 10 machine and scroll to the bottom. Please refer to the attached gif file.

Please refer to the attached sample project. When you start the application the form's text indicates how many times the AppointmentFormatting event is fired for only 30 appointments - more than 400 times. The more appointments you have , the more times the vent is initially fired,e.g. if you have 50 appointmens it is fired If you switch between the different views you will see how the counter increases its value.

How  to reproduce: public partial class Form2 : Form
{
    BindingList<AppointmenntObject> appointments;
    BindingSource bs;

    public Form2()
    {
        InitializeComponent();

        this.appointments = new BindingList<AppointmenntObject>();

        this.bs = new BindingSource();
        this.bs.DataSource = this.appointments;
        for (int i = 0; i <= 3; i++)
        {
            appointments.Add(new AppointmenntObject(DateTime.Now.AddDays(i), DateTime.Now.AddDays(i).AddHours(2), "Summary " + i, "Description" + i, "Location" + i));
        }

        AppointmentMappingInfo appointmentMappingInfo = new AppointmentMappingInfo();
        appointmentMappingInfo.Start = "Start";
        appointmentMappingInfo.End = "End";
        appointmentMappingInfo.Description = "Description";
        appointmentMappingInfo.Summary = "Summary";
        this.schedulerBindingDataSource1.EventProvider.Mapping = appointmentMappingInfo;
        schedulerBindingDataSource1.EventProvider.DataSource = this.bs;

        this.radScheduler1.DataSource = this.schedulerBindingDataSource1;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        var ev = (AppointmenntObject)this.bs.Current;
        var end = ev.End;
        ev.End = end.AddHours(1);
    }
}

public class AppointmenntObject : INotifyPropertyChanged
    {
        private DateTime start;
        private DateTime end;
        private string summary;
        private string description;
        private string location;

        public AppointmenntObject(DateTime start, DateTime end, string summary, string description, string location)
        {
            this.Start = start;
            this.End = end;
            this.Summary = summary;
            this.Description = description;
            this.Location = location;
        }

        public DateTime Start
        {
            get
            {
                return this.start;
            }
            set
            {
                if (this.start != value)
                {
                    this.start = value;
                    OnPropertyChanged("Start");
                }
            }
        }


        public DateTime End
        {
            get
            {
                return this.end;
            }
            set
            {
                if (this.end != value)
                {
                    this.end= value;
                    OnPropertyChanged("end");
                }
            }
        }

        public string Description
        {
            get
            {
                return this.description;
            }
            set
            {
                if (this.description != value)
                {
                    this.description = value;
                    OnPropertyChanged("Description");
                }
            }
        }

        public string Summary
        {
            get
            {
                return this.summary;
            }
            set
            {
                if (this.summary != value)
                {
                    this.summary= value;
                    OnPropertyChanged("Summary");
                }
            }
        }

        public string Location
        {
            get
            {
                return this.location;
            }
            set
            {
                if (this.location != value)
                {
                    this.location = value;
                    OnPropertyChanged("Location");
                }
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

Workaround: Rebind the SchedulerBindingDataSource object

private void button1_Click(object sender, EventArgs e)
{
    var ev = (AppointmenntObject)this.bs.Current;
    var end = ev.End;
    ev.End = end.AddHours(1);

    this.schedulerBindingDataSource1.Rebind();
}

To reproduce:

            Appointment a = new Appointment(DateTime.Now, TimeSpan.FromHours(20),"Meeting");
            a.StatusId = this.radScheduler1.Statuses.Last().Id;
            this.radScheduler1.Appointments.Add(a);

            this.radScheduler1.ShowAppointmentStatus = false;

The status for AppointmentElements is shown although it shouldn't.

To reproduce:
            this.radScheduler1.ActiveViewType = Telerik.WinControls.UI.SchedulerViewType.Timeline;
            this.radScheduler1.RightToLeft = System.Windows.Forms.RightToLeft.Yes;

Please refer to the attached gif file. Select the left border of an appointment and try to resize it to the left. You will notice that you are allowed to resize it to the right and vice versa.

Workaround:           this.radScheduler1.SchedulerElement.ResizeBehavior = new MyResizingBehavior(this.radScheduler1.SchedulerElement);

public class MyResizingBehavior : AppointmentResizingBehavior
{
    RadScheduler scheduler;

    public MyResizingBehavior(SchedulerVisualElement activeOwner)
        : base(activeOwner)
    {
        scheduler = activeOwner.Scheduler;
    }

    protected override bool UpdateMouseCursor(Point mousePosition, Rectangle nearRect, Rectangle farRect)
    {
        bool result = base.UpdateMouseCursor(mousePosition, nearRect, farRect);
        if (scheduler.RightToLeft == RightToLeft.Yes )
        {
            FieldInfo leftFI = typeof(AppointmentResizingBehavior).GetField("leftResize", BindingFlags.NonPublic | BindingFlags.Instance);
            FieldInfo rightFI = typeof(AppointmentResizingBehavior).GetField("rightResize", BindingFlags.NonPublic | BindingFlags.Instance);

            if (nearRect.Contains(mousePosition) && scheduler.Cursor == Cursors.SizeWE)
            {
                leftFI.SetValue(this, false);
                rightFI.SetValue(this, true);
            }
            else if (farRect.Contains(mousePosition) && scheduler.Cursor == Cursors.SizeWE)
            {
                leftFI.SetValue(this, true);
                rightFI.SetValue(this, false);
            }
        }
        return result;
    }
}

Color[] colors = new Color[]
{
    Color.LightBlue, Color.LightGreen, Color.LightYellow,
    Color.Red, Color.Orange, Color.Pink, Color.Purple, Color.Peru, Color.PowderBlue
};
string[] names = new string[]
{
    "Alan Smith", "Anne Dodsworth",
    "Boyan Mastoni", "Richard Duncan", "Maria Shnaider"
};
for (int i = 0; i < names.Length; i++)
{
    Resource resource = new Resource();
    resource.Id = new EventId(i);
    resource.Name = names[i];
    resource.Color = colors[i];
    this.radScheduler1.Resources.Add(resource);
}
this.radScheduler1.GroupType = GroupType.Resource;
this.radScheduler1.ActiveView.ResourcesPerView = 4;
this.radScheduler1.ActiveViewType = SchedulerViewType.Timeline;
this.radScheduler1.GetTimelineView().GroupSeparatorWidth = 0;

By default, the GroupSeparatorWidth property is set to 3. If you need to remove the resources separator, it is necessary to set the GroupSeparatorWidth property to 0 which is not possible at the moment with the public API.

Workaround:

FieldInfo fi = typeof(SchedulerView).GetField("groupSeparatorWidth", BindingFlags.Instance | BindingFlags.NonPublic);
fi.SetValue(this.radScheduler1.GetTimelineView(), 0);

Run the attached project and add one appointment. Press the "save" button and restart the application.

Workaround:

private void radButton1_Click(object sender, EventArgs e)
{ 
    Telerik.WinControls.UI.Appointment a = new Telerik.WinControls.UI.Appointment(DateTime.Now, TimeSpan.FromHours(2));
    this.radScheduler1.Appointments.Add(a);
    this.radScheduler1.Appointments.Remove(a);
    dbContext.SaveChanges();
}

To reproduce:

1. Add a RadScheduler on a form and set the culture:
this.radScheduler1.Culture = new System.Globalization.CultureInfo("fa-IR");

2. In regional settings set the Format to Persian(Iran) as it is illustrated in the attached screenshot.

3. Run the application and try to add an appointment. Open the Recurrence dialog and you will get the exception.

Please refer to the attached sample project and screenshot. Note that if RadScheduler is not grouped by resources, the scrollbar works as expected.

Please refer to the attached sample project. When you toggle the button the Visible property for the first resource is inverted. However, it doesn't take effect in RadScheduler and the resource is always visible.

Workaround: Currently, if you want to hide some of the resources, you should remove them from the Resources collection of RadScheduler. When you want to use them again, you should just add them to the same collection.

To reproduce: Use the following code snippet:

            DateTime dt = DateTime.Now;
            this.radScheduler1.Appointments.Add(new Appointment(dt, TimeSpan.FromHours(4),"A1"));
            this.radScheduler1.Appointments.Add(new Appointment(dt, TimeSpan.FromHours(4),"A2"));

By default, when two appointments start at the same time, on the left side it is displayed the shorter appointment. Hence, if you start resizing an appointment it may jump to another location leaving the mouse in a  wrong and inconsistent position.  The attached gif illustartes the behavior.

Workaround: 

public RadForm1()
{
    InitializeComponent();

    this.radScheduler1.ElementProvider = new MyElementProvider(this.radScheduler1);

    DateTime dt = DateTime.Now;
    this.radScheduler1.Appointments.Add(new Appointment(dt, TimeSpan.FromHours(4),"A1"));
    this.radScheduler1.Appointments.Add(new Appointment(dt, TimeSpan.FromHours(4),"A2"));
}

private class AppointmentDateInfo : IComparable
{
    public AppointmentElement appointment;
    public DateTime date;
    public bool isEnd;
    private DateTimeComparer comparer;

    public AppointmentDateInfo(AppointmentElement appointment, DateTime date, bool isEnd)
    {
        this.comparer = new DateTimeComparer(appointment.Scheduler);
        this.appointment = appointment;
        this.date = date;
        this.isEnd = isEnd;
    }

    public int CompareTo(object obj)
    {
        AppointmentDateInfo other = obj as AppointmentDateInfo;
        if (other == null)
        {
            return 1;
        }

        int res = date.CompareTo(other.date);
        if (res == 0)
        {
            if (other.appointment != this.appointment)
            {
                res = other.isEnd.CompareTo(isEnd);
            }
            else
            {
                res = this.isEnd.CompareTo(other.isEnd);
            }
        }
        if (appointment.Start.Equals(other.appointment.Start))
        {
            return res != 0 ? res : appointment.AppointmentSubject.CompareTo(other.appointment.AppointmentSubject);
        }
        return res != 0 ? res : comparer.Compare(appointment, other.appointment);
    }
}

public class MyElementProvider : SchedulerElementProvider
{
    public MyElementProvider(RadScheduler scheduler) : base(scheduler)
    {
    }

    protected override T CreateElement<T>(SchedulerView view, object context)
    {
        if (typeof(T) == typeof(DayViewAppointmentsTable))
        {
            return new CustomDayViewAppointmentsTable(this.Scheduler, view, (DayViewAppointmentsArea)context)as T;
        }
        
        return base.CreateElement<T>(view, context);
    }
}

public class CustomDayViewAppointmentsTable : DayViewAppointmentsTable
{
    public CustomDayViewAppointmentsTable(RadScheduler scheduler, SchedulerView view, DayViewAppointmentsArea area) : base(scheduler, view, area)
    {
    }

    private int FindLaneSpan(AppointmentElement appointment, Dictionary<AppointmentElement, int> appointmentLanes, int maxLanes)
    {
        int lane = appointmentLanes[appointment];
        int span = maxLanes - lane;

        int cellsPerHour = this.GetDayViewBase().GetNumberOfCellsPerHour();
        int minutesPerSlot = 60 / cellsPerHour;

        DateTime roundedAppStart = this.GetRulerRoundedDateTime(appointment.Start, false);
        DateTime roundedAppEnd = this.GetRulerRoundedDateTime(appointment.End, true);

        if (appointment.Start == appointment.End)
        {
            roundedAppEnd = roundedAppEnd.AddMinutes(minutesPerSlot);
        }

        foreach (KeyValuePair<AppointmentElement, int> item in appointmentLanes)
        {
            if (appointment == item.Key)
            {
                continue;
            }

            DateTime roundedItemStart = this.GetRulerRoundedDateTime(item.Key.Start, false);
            DateTime roundedItemEnd = this.GetRulerRoundedDateTime(item.Key.End, true);

            if (item.Key.Start == item.Key.End)
            {
                roundedItemEnd = roundedItemEnd.AddMinutes(minutesPerSlot);
            }

            if (roundedItemStart < roundedAppEnd && roundedItemEnd > roundedAppStart && item.Value > lane)
            {
                span = Math.Min(span, item.Value - lane);
            }
        }

        return span;
    }

    private int FindFreeLane(List<AppointmentElement> overlappingAppointments, Dictionary<AppointmentElement, int> appointmentLanes)
    {
        List<int> indexes = new List<int>();

        for (int i = 0; i < overlappingAppointments.Count; i++)
        {
            indexes.Add(appointmentLanes[overlappingAppointments[i]]);
        }

        indexes.Sort();

        for (int i = 0; i < indexes.Count; i++)
        {
            if (i < indexes[i])
            {
                return i;
            }
        }

        return overlappingAppointments.Count;
    }
    
    protected override void ArrangeAppointments(SizeF finalSize)
    {
        RectangleF containerRect = new RectangleF(PointF.Empty, finalSize);
        List<AppointmentElement> appointmentsInLayout = new List<AppointmentElement>();

        foreach (AppointmentElement element in this.AppointmentElements)
        {
            if (element.Visibility != ElementVisibility.Collapsed)
            {
                appointmentsInLayout.Add(element);
            }
        }

        appointmentsInLayout.Sort(new DateTimeComparer(this.Scheduler));
        Dictionary<AppointmentElement, object> arrangedAppointments = new Dictionary<AppointmentElement, object>();

        foreach (AppointmentElement appointmentElement in appointmentsInLayout)
        {
            if (arrangedAppointments.ContainsKey(appointmentElement))
            {
                continue;
            }

            appointmentElement.RelatedAppointments.Sort(new DateTimeComparer(this.Scheduler));

            List<AppointmentDateInfo> appointmentDates = new List<AppointmentDateInfo>();
            List<AppointmentElement> overlappingAppointments = new List<AppointmentElement>();
            Dictionary<AppointmentElement, int> appointmentLanes = new Dictionary<AppointmentElement, int>();

            foreach (AppointmentElement relatedAppointment in appointmentElement.RelatedAppointments)
            {
                if (relatedAppointment.Visibility == ElementVisibility.Collapsed)
                {
                    continue;
                }

                DateTime appStart = relatedAppointment.Start <= relatedAppointment.End ? relatedAppointment.Start : relatedAppointment.End;
                DateTime appEnd = relatedAppointment.Start <= relatedAppointment.End ? relatedAppointment.End : relatedAppointment.Start;

                if (!this.Scheduler.EnableExactTimeRendering)
                {
                    if (appStart != appEnd)
                    {
                        appointmentDates.Add(new AppointmentDateInfo(relatedAppointment, this.GetRulerRoundedDateTime(appStart, false), false));
                        appointmentDates.Add(new AppointmentDateInfo(relatedAppointment, this.GetRulerRoundedDateTime(appEnd, true), true));
                    }
                    else
                    {
                        int cellsPerHour = this.GetDayViewBase().GetNumberOfCellsPerHour();
                        int minutesPerSlot = 60 / cellsPerHour;

                        appointmentDates.Add(new AppointmentDateInfo(relatedAppointment, this.GetRulerRoundedDateTime(appStart, false), false));
                        appointmentDates.Add(new AppointmentDateInfo(relatedAppointment, this.GetRulerRoundedDateTime(appEnd, true).AddMinutes(minutesPerSlot),
                            true));
                    }
                }
                else
                {
                    appointmentDates.Add(new AppointmentDateInfo(relatedAppointment, appStart, false));
                    appointmentDates.Add(new AppointmentDateInfo(relatedAppointment, appEnd, true));
                }
            }

            appointmentDates.Sort();
            int maxLanesCount = 0;

            for (int i = 0; i < appointmentDates.Count; i++)
            {
                if (!appointmentDates[i].isEnd)
                {
                    int freeLane = FindFreeLane(overlappingAppointments, appointmentLanes);
                    appointmentLanes.Add(appointmentDates[i].appointment, freeLane);
                    overlappingAppointments.Add(appointmentDates[i].appointment);
                    maxLanesCount = Math.Max(maxLanesCount, freeLane + 1);
                }
                else
                {
                    overlappingAppointments.Remove(appointmentDates[i].appointment);
                }

                if (overlappingAppointments.Count == 0)
                {
                    foreach (KeyValuePair<AppointmentElement, int> item in appointmentLanes)
                    {
                        AppointmentElement appointment = item.Key;
                        int lane = item.Value;
                        DateTime rulerRoundStart = this.GetRulerRoundedDateTime(appointment.Start, false);
                        DateTime rulerRoundEnd = this.GetRulerRoundedDateTime(appointment.End, true);

                        if (appointment.Start == appointment.End)
                        {
                            int cellsPerHour = this.GetDayViewBase().GetNumberOfCellsPerHour();
                            int minutesPerSlot = 60 / cellsPerHour;

                            rulerRoundEnd = rulerRoundEnd.AddMinutes(minutesPerSlot);
                        }

                        PointF location = GetItemLocationInTable(appointment.Start, finalSize);

                        float dayWidth = this.Area.DayViewElement.GetColumnWidth(this.Area.DayViewElement.GetColumnForDate(rulerRoundStart), finalSize.Width);
                        int laneSpan = FindLaneSpan(appointment, appointmentLanes, maxLanesCount);

                        SizeF size = new SizeF(dayWidth / maxLanesCount * laneSpan, this.GetItemHeight(appointment.Start, appointment.End));
                        location.X += dayWidth / maxLanesCount * lane + this.Area.DayViewElement.AppointmentMargin.Left;
                        location.Y += this.Area.DayViewElement.AppointmentMargin.Top;
                        size.Width -= this.Area.DayViewElement.AppointmentMargin.Horizontal;

                        appointment.DesiredBounds = this.OnAppointmentLayout(appointment, new RectangleF(location, size), finalSize);
                        if (!arrangedAppointments.ContainsKey(appointment))
                        {
                            arrangedAppointments.Add(appointment, null);
                        }
                    }

                    appointmentLanes.Clear();
                    maxLanesCount = 0;
                }
            }

            for (int i = 0; i < appointmentsInLayout.Count; i++)
            {
                AppointmentElement appointment = appointmentsInLayout[i];

                if (appointment.Visibility != ElementVisibility.Visible)
                    continue;

                RectangleF rectangle = appointment.DesiredBounds;

                if (this.RightToLeft)
                {
                    rectangle = LayoutUtils.RTLTranslateNonRelative(rectangle, containerRect);
                }

                appointment.Arrange(rectangle);
            }
        }
    }
}

To reproduce: please refer to the attached sample project and run it. Try to edit the existing appointment by using the inline editor. As a result, the AppointmentAdded event will be fired. You will notice that the Appointments collection contains more appointments than the existing ones. Note that if you use the edit dialog, this event is not fired and the behavior is as expected.

Workaround: RadScheduler1.SchedulerElement.EditorManager.EditorViewMode = SchedulerEditorViewMode.EditorDialog

To reproduce:
- Bind the scheduler using  SchedulerBindingDataSource and group by resources.
- At runtime change the data source of the SchedulerBindingDataSource.
- A System.ArgumentException is thrown. 

To reproduce: please refer to the attached sample project. Edit some appointment by changing its name or time slot. In the AppointmentChanged event the changes are stored to database. However, if you restart the application you will notice that the changes are not saved at all. 

Workaround: call the IEditableObject.EndEdit method for the affected record before saving the changes to the database.

private void RadScheduler1_AppointmentChanged(object sender, AppointmentChangedEventArgs e)
{
    IEditableObject editableObject = e.Appointment.DataItem as IEditableObject;
    if (editableObject!=null)
    {
        editableObject.EndEdit();
    }
    SaveChanges();
}

How to reproduce:
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        this.radScheduler1.AppointmentAdded += radScheduler1_AppointmentAdded;

        Appointment appointment = new Appointment(DateTime.Now, TimeSpan.FromMinutes(60), "Summary", "Description");
        appointment.StatusId = 2;
        appointment.BackgroundId = 6;
        this.radScheduler1.Appointments.Add(appointment);
    }

    private void radScheduler1_AppointmentAdded(object sender, AppointmentAddedEventArgs e)
    {
        Console.WriteLine("AppointmentAdded");
    }
}

Workaround:
public Form1()
        {
            InitializeComponent();

            this.radScheduler1.Appointments.CollectionChanged += Appointments_CollectionChanged;

            Appointment appointment = new Appointment(DateTime.Now, TimeSpan.FromMinutes(60), "Summary", "Description");
            appointment.StatusId = 2;
            appointment.BackgroundId = 6;
            this.radScheduler1.Appointments.Add(appointment);
        }

        private void Appointments_CollectionChanged(object sender, Telerik.WinControls.Data.NotifyCollectionChangedEventArgs e)
        {
            if (e.Action == Telerik.WinControls.Data.NotifyCollectionChangedAction.Add)
            {
                Console.WriteLine("AppointmentAdded");    
            }
        }

To reproduce:
Image img1;
Image img2;
public RadForm1()
{
    InitializeComponent();
    new Telerik.WinControls.RadControlSpy.RadControlSpyForm().Show();
    img1 = Image.FromFile(@"..\..\delete.png");
    img2 = Image.FromFile(@"..\..\111.png");

    Color[] colors = new Color[]{Color.LightBlue, Color.LightGreen, Color.LightYellow,
.Red, Color.Orange, Color.Pink, Color.Purple, Color.Peru, Color.PowderBlue};
    string[] names = new string[]{"Alan Smith", "Anne Dodsworth",
n Mastoni", "Richard Duncan", "Maria Shnaider"};
    for (int i = 0; i < names.Length; i++)
    {
        Resource resource = new Resource();
        resource.Id = new EventId(i);
        resource.Name = names[i];
        resource.Color = colors[i];
        resource.Image = img2;
        this.radScheduler1.Resources.Add(resource);
    }

    this.radScheduler1.ActiveView.ResourcesPerView = 2;
    this.radScheduler1.GroupType = GroupType.Resource;

    SchedulerDayViewGroupedByResourceElement dayView = this.radScheduler1.SchedulerElement.ViewElement as SchedulerDayViewGroupedByResourceElement;
    
    dayView.ResourceHeaderHeight = 120;

    radScheduler1.AppointmentFormatting += RadScheduler1_AppointmentFormatting;

    radScheduler1.Appointments.Add(new Appointment(DateTime.Now.AddHours(-7), DateTime.Now.AddHours(-5), "Summary", "Description") { ResourceId = radScheduler1.Resources[0].Id });
   
}

private void RadScheduler1_AppointmentFormatting(object sender, SchedulerAppointmentEventArgs e)
{
    e.AppointmentElement.Image = img1

}

- Drag the appointment to the top if needed.
- Scroll down.

Workaround:

private void RadScheduler1_AppointmentFormatting(object sender, SchedulerAppointmentEventArgs e)
{
    if (e.AppointmentElement.Children.Count ==0)
    {
        LightVisualElement el = new LightVisualElement();
        el.DrawImage = true;
        el.Image = img1;
        e.AppointmentElement.Children.Add(el);
    }
}

Please refer to the attached sample project and gif file.

Workaround: this.radScheduler1.ElementProvider = new CustomSchedulerElementProvider(this.radScheduler1);

public class CustomSchedulerElementProvider : SchedulerElementProvider
{ 
    public CustomSchedulerElementProvider(RadScheduler scheduler) : base(scheduler)
    {
    }

    protected override T CreateElement<T>(SchedulerView view, object context)
    {
        if (typeof(T) == typeof(TimelineGroupingByResourcesElement))
        {
            return new CustomTimelineGroupingByResourcesElement(this.Scheduler,view)as T;
        }
         
        return base.CreateElement<T>(view, context);
    }
}

public class CustomTimelineGroupingByResourcesElement : TimelineGroupingByResourcesElement
{
    public CustomTimelineGroupingByResourcesElement(RadScheduler scheduler, SchedulerView view) : base(scheduler, view)
    {
    }

    protected override SizeF ArrangeOverride(SizeF finalSize)
    {
        RectangleF contentRect = new RectangleF(PointF.Empty, finalSize);
        int vScrollOffset = this.View.AllowResourcesScrolling ? this.ResourceScrollBarThickness : 0;

        if (this.VScrollBar != null && this.VScrollBar.Maximum < this.VScrollBar.LargeChange)
        {
            vScrollOffset = 0;
        }

        IList<SchedulerTimelineViewElement> timelineElements = this.GetChildViewElements();
        IList<LightVisualElement> viewSeparators = this.GetViewSeparators();

        List<RectangleF> resourcesBounds = new List<RectangleF>();
        List<RectangleF> separatorsBounds = new List<RectangleF>();

        int scrollBarOffset = 0;

        if (timelineElements.Count > 0)
        {
            if (timelineElements[timelineElements.Count - 1].NavigationElement.Visibility == ElementVisibility.Visible)
            {
                scrollBarOffset = 17;
            }
        }

        int headerHeight = 0;
        if (timelineElements.Count > 0 && timelineElements[0].Header.Visibility != ElementVisibility.Collapsed)
        {
            headerHeight = timelineElements[0].ViewHeaderHeight + timelineElements[0].ColumnHeaderHeight;
        }
        FieldInfo fi = typeof(TimelineGroupingByResourcesElement).GetField("leftCell", BindingFlags.Instance | BindingFlags.NonPublic);
        SchedulerCellElement leftCell = fi.GetValue(this) as SchedulerCellElement;
        FieldInfo fi2 = typeof(TimelineGroupingByResourcesElement).GetField("bottomCell", BindingFlags.Instance | BindingFlags.NonPublic);
        SchedulerCellElement bottomCell = fi2.GetValue(this) as SchedulerCellElement;
        if (leftCell != null)
        {
            RectangleF arrangeRectangle = new RectangleF(0, 0, ResourceHeaderWidth, headerHeight);
            if (this.RightToLeft)
            {
                arrangeRectangle = LayoutUtils.RTLTranslateNonRelative(arrangeRectangle, contentRect);
            }

            leftCell.Arrange(arrangeRectangle);
        }

        if (bottomCell != null)
        {
            RectangleF arrangeRectangle = new RectangleF(0, finalSize.Height - scrollBarOffset, ResourceHeaderWidth, scrollBarOffset);
            if (this.RightToLeft)
            {
                arrangeRectangle = LayoutUtils.RTLTranslateNonRelative(arrangeRectangle, contentRect);
            }

            bottomCell.Arrange(arrangeRectangle);
        }

        float separatorsWidth = this.View.GroupSeparatorWidth * (this.View.ResourcesPerView - 1);
        float resourcesHeight = finalSize.Height - separatorsWidth - headerHeight ;
        float y = 0;

        for (int i = 0; i < timelineElements.Count; i++)
        {
            SchedulerTimelineViewElement timelineElement = timelineElements[i];
            LightVisualElement separator = i < viewSeparators.Count ? viewSeparators[i] : null;

            if (timelineElement != null)
            {
                float calculatedHeight = this.GetResourceSize(i, resourcesHeight);
                RectangleF arrangeRect = new RectangleF(this.ResourceHeaderWidth, y,
                    finalSize.Width - this.ResourceHeaderWidth - vScrollOffset, calculatedHeight);

                if (i == 0)
                {
                    arrangeRect.Height += headerHeight;
                }
                else if (i == timelineElements.Count - 1)
                {
                    arrangeRect.Height = finalSize.Height - arrangeRect.Top - 1;
                }

                if (this.RightToLeft)
                {
                    arrangeRect = LayoutUtils.RTLTranslateNonRelative(arrangeRect, contentRect);
                }

                timelineElement.Arrange(arrangeRect);

                y += arrangeRect.Height;

                if (i == 0)
                {
                    arrangeRect.Height -= headerHeight;
                }
                else
                {
                    arrangeRect.Y -= headerHeight;
                }

                resourcesBounds.Add(arrangeRect);
            }

            if (separator != null)
            {
                float calculatedHeight = this.View.GroupSeparatorWidth;
                RectangleF arrangeRect = new RectangleF(this.ResourceHeaderWidth, y,
                    finalSize.Width - this.ResourceHeaderWidth - vScrollOffset, calculatedHeight);
                if (this.RightToLeft)
                {
                    arrangeRect = LayoutUtils.RTLTranslateNonRelative(arrangeRect, contentRect);
                }

                separator.Arrange(arrangeRect);
                arrangeRect.Y -= headerHeight;
                separatorsBounds.Add(arrangeRect);
                y += calculatedHeight;
            }
        }

        if (this.ResourcesHeader != null)
        {
            RectangleF arrangeRectangle = new RectangleF(0, headerHeight,
                this.ResourceHeaderWidth, finalSize.Height - scrollBarOffset - headerHeight);
            if (this.RightToLeft)
            {
                arrangeRectangle = LayoutUtils.RTLTranslateNonRelative(arrangeRectangle, contentRect);
            }
            this.ResourcesHeader.SetResourcesLayoutInfo(resourcesBounds, separatorsBounds);
            this.ResourcesHeader.Arrange(arrangeRectangle);
        }

        if (this.View.AllowResourcesScrolling)
        {
            RectangleF scrollbarRect = new RectangleF(finalSize.Width - vScrollOffset,
                0, vScrollOffset, finalSize.Height - scrollBarOffset);
            if (this.RightToLeft)
            {
                scrollbarRect = LayoutUtils.RTLTranslateNonRelative(scrollbarRect, contentRect);
            }

            this.VScrollBar.Arrange(scrollbarRect);
        }
        else
        {
            this.VScrollBar.Arrange(RectangleF.Empty);
        }

        return finalSize;
    }
}