Hello,
Can I stop the grid from being rendered while manipulating data, and making it render again only at a specific point?

Now I have serious performance issues, which seems to be caused by over re-measuring of the grid.

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using Telerik.Windows.Controls;
using Telerik.Windows.Controls.DragDrop;
using Telerik.Windows.Controls.ScheduleView;
 
namespace WpfApplication3
{
	public class ListBoxDragDropBehavior : Freezable
	{
		public static readonly DependencyProperty AppointmentTemplateProperty =
			DependencyProperty.Register("AppointmentTemplate", typeof(DataTemplate), typeof(ListBoxDragDropBehavior), null);
 
		public static readonly DependencyProperty EffectivePixelLengthProperty =
			DependencyProperty.Register("EffectivePixelLength", typeof(TimeSpan), typeof(ListBoxDragDropBehavior), null);
 
		public static readonly DependencyProperty EffectiveOrientationProperty =
			DependencyProperty.Register("EffectiveOrientation", typeof(Orientation), typeof(ListBoxDragDropBehavior), null);
 
		public static readonly DependencyProperty BehaviorProperty =
			DependencyProperty.RegisterAttached("Behavior", typeof(ListBoxDragDropBehavior), typeof(ListBoxDragDropBehavior), new PropertyMetadata(new PropertyChangedCallback(OnBehaviorChanged)));
 
		public DataTemplate AppointmentTemplate
		{
			get { return (DataTemplate)GetValue(AppointmentTemplateProperty); }
			set { SetValue(AppointmentTemplateProperty, value); }
		}
 
		public TimeSpan EffectivePixelLength
		{
			get { return (TimeSpan)GetValue(EffectivePixelLengthProperty); }
			set { SetValue(EffectivePixelLengthProperty, value); }
		}
 
		public Orientation EffectiveOrientation
		{
			get { return (Orientation)GetValue(EffectiveOrientationProperty); }
			set { SetValue(EffectiveOrientationProperty, value); }
		}
        
		public static ListBoxDragDropBehavior GetBehavior(DependencyObject obj)
		{
			return (ListBoxDragDropBehavior)obj.GetValue(BehaviorProperty);
		}
 
		public static void SetBehavior(DependencyObject obj, ListBoxDragDropBehavior value)
		{
			obj.SetValue(BehaviorProperty, value);
		}
 
		protected override Freezable CreateInstanceCore()
		{
			return new ListBoxDragDropBehavior();
		}
 
		private static void OnBehaviorChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
		{
			System.Windows.Controls.ListBox listBox = d as System.Windows.Controls.ListBox;
			if (listBox == null)
			{
				return;
			}
 
			ListBoxDragDropBehavior behavior = (ListBoxDragDropBehavior)e.OldValue;
			if (behavior != null)
			{
				RadDragAndDropManager.RemoveDragQueryHandler(listBox, new EventHandler<DragDropQueryEventArgs>(behavior.OnDragQuery));
				RadDragAndDropManager.RemoveDropQueryHandler(listBox, new EventHandler<DragDropQueryEventArgs>(behavior.OnDropQuery));
				RadDragAndDropManager.RemoveDropInfoHandler(listBox, new EventHandler<DragDropEventArgs>(behavior.OnDropInfo));
			}
 
			behavior = (ListBoxDragDropBehavior)e.NewValue;
			if (behavior != null)
			{
				RadDragAndDropManager.SetAllowDrop(listBox, true);
				RadDragAndDropManager.AddDragQueryHandler(listBox, new EventHandler<DragDropQueryEventArgs>(behavior.OnDragQuery));
				RadDragAndDropManager.AddDropQueryHandler(listBox, new EventHandler<DragDropQueryEventArgs>(behavior.OnDropQuery));
				RadDragAndDropManager.AddDropInfoHandler(listBox, new EventHandler<DragDropEventArgs>(behavior.OnDropInfo));
			}
		}
 
		private void OnDragQuery(object sender, DragDropQueryEventArgs e)
		{
			if (e.Options.Status == DragStatus.DragQuery)
			{
				System.Windows.Controls.ListBox listbox = sender as System.Windows.Controls.ListBox;
 
				IList<IOccurrence> appointments = listbox.SelectedItems.OfType<IOccurrence>().ToList();
 
				if (appointments.Count == 0)
				{
					return;
				}
 
				e.Options.DragCue = this.CreateDragCue(appointments);
				e.Options.Payload = new ScheduleViewDragDropPayload(listbox.ItemsSource, appointments);
			}
 
			e.QueryResult = true;
		}
 
		private void OnDropQuery(object sender, DragDropQueryEventArgs e)
		{
			e.QueryResult = e.Options.Payload is ScheduleViewDragDropPayload;
		}
 
		private void OnDropInfo(object sender, DragDropEventArgs e)
		{
            System.Windows.Controls.ListBox listBox = sender as System.Windows.Controls.ListBox;
 
			if (e.Options.Status == DragStatus.DropPossible)
			{
				RadDragAndDropManager.Options.Effects = DragDropEffects.All;
				RadDragAndDropManager.Options.CurrentCursor = System.Windows.Input.Cursors.Arrow;
			}
 
            //If the user has dropped - and the drag was made FROM the scheduleview TO the listbox
			if (e.Options.Status == DragStatus.DropComplete && !listBox.IsAncestorOf(e.Options.Source))
			{
				ScheduleViewDragDropPayload payload = e.Options.Payload as ScheduleViewDragDropPayload;
				if (payload != null)
				{
					(payload.SourceAppointmentsSource as IList).RemoveAll((object i) => payload.DraggedAppointments.OfType<object>().Contains(i));
					(listBox.ItemsSource as IList).AddRange(payload.DraggedAppointments);
				}
			}
		}
 
		private ContentControl CreateDragCue(IEnumerable<IOccurrence> appointments)
		{
			bool isHorizontal = this.EffectiveOrientation == Orientation.Horizontal;
			double ticksPerPixel = this.EffectivePixelLength.Ticks;
 
			StackPanel panel = new StackPanel();
			panel.Orientation = this.EffectiveOrientation;
			panel.Background = new SolidColorBrush() { Color = Colors.Transparent };
 
			foreach (IOccurrence appointment in appointments)
			{
				double lenght = appointment.Duration().Ticks / ticksPerPixel;
 
				AppointmentCueItem item = new AppointmentCueItem();
				item.HorizontalContentAlignment = HorizontalAlignment.Stretch;
				item.VerticalContentAlignment = VerticalAlignment.Stretch;
				item.Height = isHorizontal ? 110 : lenght;
				item.Width = isHorizontal ? lenght : 110;
				item.Content = appointment;
				item.ContentTemplate = this.AppointmentTemplate;
 
				panel.Children.Add(item);
			}
 
			ContentControl cue = new ContentControl();
			cue.Content = panel;
 
			return cue;
		}
	}
}

        <telerik:RadScheduleView Name="radScheduleView1"
                                 EditAppointmentDialogStyle="{StaticResource EditAppointmentDialogStyle}"
                                 Grid.Column="1"
                                 AppointmentItemContentTemplate="{StaticResource AppointmentItemContentTemplate}"
                                 GroupHeaderContentTemplateSelector="{StaticResource GroupHeaderContentTemplateSelector}">
            <telerik:RadScheduleView.ViewDefinitions>
                <my:DayViewDefinition />
                <my:WeekViewDefinition />
                <my:MonthViewDefinition />
                <my:TimelineViewDefinition />
            </telerik:RadScheduleView.ViewDefinitions>
 
            <scheduleView:RadScheduleView.GroupDescriptionsSource>
                <scheduleView:GroupDescriptionCollection>
                    <scheduleView:ResourceGroupDescription ResourceType="Operatives" />
                </scheduleView:GroupDescriptionCollection>
            </scheduleView:RadScheduleView.GroupDescriptionsSource>
 
        </telerik:RadScheduleView>
 
        <ListBox AllowDrop="True" ItemsSource="{Binding}" Name="listBox1"
                 ItemContainerStyle="{StaticResource ListBoxItemContainerStyle}"
                 ItemTemplate="{StaticResource ListBoxItemTemplate}" SelectionMode="Extended"
                 HorizontalAlignment="Left" Width="270">
            <local:ListBoxDragDropBehavior.Behavior>
                <local:ListBoxDragDropBehavior EffectivePixelLength="{Binding EffectivePixelLength, ElementName=radScheduleView1}"
                                               EffectiveOrientation="{Binding EffectiveOrientation, ElementName=radScheduleView1}"
                                               AppointmentTemplate="{Binding DragVisualCueItemTemplate, ElementName=radScheduleView1}" />
            </local:ListBoxDragDropBehavior.Behavior>
            <ListBox.Background>
                <LinearGradientBrush EndPoint="0.5,1" MappingMode="RelativeToBoundingBox" StartPoint="0.5,0">
                    <GradientStop Color="#FF4B4B4B" Offset="1" />
                    <GradientStop Color="#FF6E6E6E" />
                </LinearGradientBrush>
            </ListBox.Background>
        </ListBox>