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);
    }
}

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");    
            }
        }

Workaround: create a derivative of the EditAppointmentDialog. Open the designer and adjust the form's height and button's position. Then replace the default dialog with the custom one: 

public RadForm1()
{
    InitializeComponent();
    this.radScheduler1.AppointmentEditDialogShowing += radScheduler1_AppointmentEditDialogShowing;
}
CustomEditAppointmentDialog dialog;
private void radScheduler1_AppointmentEditDialogShowing(object sender, Telerik.WinControls.UI.AppointmentEditDialogShowingEventArgs e)
{
    if (dialog==null)
    {
        dialog = new CustomEditAppointmentDialog();
    }
    e.AppointmentEditDialog = dialog;
}

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: please run the attached sample project and have a look at the gif file.

Workaround: in the _HideWeekDays method, don't pass 0 width as a parameter in the SetColumnWidth method. Use 0.01 instead.

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();
}

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;
    }
}

To reproduce:

Appointment a1 = new Appointment(DateTime.Today.AddHours(10).AddMinutes(30), TimeSpan.FromMinutes(30), "A1");
Appointment a2 = new Appointment(DateTime.Today.AddHours(11) , TimeSpan.FromMinutes(30), "A2");
Appointment a3 = new Appointment(DateTime.Today.AddHours(11).AddMinutes(30), TimeSpan.FromMinutes(30), "A3");
this.radScheduler1.Appointments.Add(a1);
this.radScheduler1.Appointments.Add(a2);
this.radScheduler1.Appointments.Add(a3); 
this.radScheduler1.ActiveViewType = SchedulerViewType.Timeline;   
SchedulerTimelineView timelineView = radScheduler1.GetTimelineView();
timelineView.ShowTimescale(Timescales.Minutes);
timelineView.GetScaling().DisplayedCellsCount = 10;

Please refer to the attached sample project which incorrect behavior when scrolling is illustrated in the attached gif file.

Workaround: instead of specifying 30 minutes duration of an appointment, use 29 minutes and 59 seconds.

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: 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: 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);
            }
        }
    }
}

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.

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

To reproduce:

1. Add a RadScheduler and associate a RadSchedulerNavigator to it.
2. Change the culture to  "fa-IR". When running the application you will notice that the time range in the navigator is not displayed correctly considering the culture of the associate RadScheduler.

Note: you can set the SchedulerNavigatorElement.DateFormat property to  "dd dddd". Thus, the time range should be displayed in a similar way as the header cells in RadScheduler.

Workaround: you can controls what to be displayed in the navigator by the SchedulerNavigatorElement.DateLabel.Text property.

            this.radScheduler1.Culture = new System.Globalization.CultureInfo("fa-IR");

            string start = this.radScheduler1.ActiveView.StartDate.ToString(this.radSchedulerNavigator1.SchedulerNavigatorElement.DateFormat, this.radScheduler1.Culture);
            string end = this.radScheduler1.ActiveView.EndDate.ToString(this.radSchedulerNavigator1.SchedulerNavigatorElement.DateFormat, this.radScheduler1.Culture);
            this.radSchedulerNavigator1.SchedulerNavigatorElement.DateLabel.Text = start + " - " + end;

By default, each Appointment has two properties: ResourceId and ResourceIds. Usually, the ResourceId is used when you have only a single resource for the appointment. In case you have multiple resources for an appointment the ResourceIds collection is used. However, the current implementation of the EditAppointmentDialog uses a RadDropDownList for the resource selection. Thus, the user is not allowed to create an appointment and assign two resources to it. It can be achieved only programmatically. This is a common scenario when creating a meeting and you have at least two participants. A possible solution would be to replace the resources RadDropDownList with a RadCheckedDropDownList. Thus, the user will be able to select multiple resources.

This feature is required for OpenEdge scenarios. 

A common case is that the resource_id field is stored as an integer field in your DataSource. But RadScheduler needs EventId type. You can have a look at the Appointment.ResourceId property which expects EventId value, not an integer. It is necessary to use a SchedulerMapping in this case and convert the integer value to EventId used by RadScheduler and convert the EventId to an integer used by your DataSource. This conversion is performed by the ConvertToDataSource and ConvertToScheduler callbacks. It is responsible for the proper conversion of the integer resource_id value coming from the DataSource to the RadScheduler's EventId. Additional information for the SchedulerMapping is available here: http://docs.telerik.com/devtools/winforms/scheduler/data-binding/scheduler-mapping

In C#, it is just necessary to specify the name of the callback which will handle the conversion but it seems to be a problem in ABL. It is required to have events.

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 set the ResourcesPerView property first to a value greater than the available resources in RadScheduler and then add even more resources, incorrect layout is displayed. Please refer to the attached gif file. However, note that if you first add the resources and then manipulate the ResourcesPerView property, everything is OK. 

Workaround: set the ResourcesPerView property considering the available resources in RadScheduler

    Private Sub RadSpinEditor2_ValueChanged(sender As Object, e As EventArgs) Handles RadSpinEditor2.ValueChanged
        Me.RadScheduler1.Resources.Clear()

        For i As Integer = 1 To Me.RadSpinEditor2.Value
            Dim resource As New Telerik.WinControls.UI.Resource()
            resource.Id = New EventId(i)
            resource.Name = "Resource" & i
            resource.Visible = True
            resource.Color = Color.LightBlue

            Me.RadScheduler1.Resources.Add(resource)
        Next i
         
        Me.RadScheduler1.GroupType = GroupType.Resource
        Me.RadScheduler1.ActiveView.ResourcesPerView = Math.Min(Me.RadScheduler1.Resources.Count, Me.RadSpinEditor1.Value)
    End Sub

By design, the month view in RadScheduler stacks the appointments for a certain day considering the start time of the appointments and their duration. Internally, it uses MonthViewEventsComparer which would be great to be replaceable somehow. 

To reproduce:

            this.radScheduler1.ActiveViewType = Telerik.WinControls.UI.SchedulerViewType.Month;

            SchedulerMonthView monthView = this.radScheduler1.GetMonthView();
            DateTime start= new DateTime(2018, 8, 1);
            DateTime end= new DateTime(2018,8,31);
            monthView.ShowFullMonth = true;
            monthView.StartDate=start;
            monthView.RangeStartDate = start;
            monthView.RangeEndDate = end;

You will notice that you can navigate outside the specified range.

Workaround: manipulate the start date of the view:
this.radScheduler1.ActiveView.PropertyChanged += ActiveView_PropertyChanged;

        DateTime start = new DateTime(2018, 8, 1);
        DateTime end = new DateTime(2018,8,31);

        private void ActiveView_PropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            if (e.PropertyName == "StartDate" && (this.radScheduler1.ActiveView.StartDate < start || start.AddDays(30) < this.radScheduler1.ActiveView.StartDate) 
                || e.PropertyName == "WeekCount" && this.radScheduler1.ActiveView.EndDate > end)
            {
                this.radScheduler1.ActiveView.StartDate = start;
            }
        }