System.IndexOutOfRangeException was unhandled by user code

  Message=Index was outside the bounds of the array.

  Source=mscorlib

  StackTrace:

       at System.Text.StringBuilder.get_Chars(Int32 index)

       at Telerik.Windows.Controls.RadMaskedInputBase.ClearString(String text, Int32 start, Int32 end, Boolean clearPlaceholders) in c:\TB\105\WPF_Scrum\Current_HotFix\Sources\Controls\Input\MaskedInput\RadMaskedInputBase.cs:line 2847

       at Telerik.Windows.Controls.RadMaskedInputBase.ClearString(String str, Boolean clearPlaceholders) in c:\TB\105\WPF_Scrum\Current_HotFix\Sources\Controls\Input\MaskedInput\RadMaskedInputBase.cs:line 2833

       at Telerik.Windows.Controls.RadMaskedInputBase.CoerceDisplayText() in c:\TB\105\WPF_Scrum\Current_HotFix\Sources\Controls\Input\MaskedInput\RadMaskedInputBase.cs:line 2431

       at Telerik.Windows.Controls.RadMaskedInputBase.CoerceValue(UpdateValueEvent updateEvent) in c:\TB\105\WPF_Scrum\Current_HotFix\Sources\Controls\Input\MaskedInput\RadMaskedInputBase.cs:line 2419

       at Telerik.Windows.Controls.RadMaskedInputBase.OnKeyDownHandled(Char c) in c:\TB\105\WPF_Scrum\Current_HotFix\Sources\Controls\Input\MaskedInput\RadMaskedInputBase.cs:line 502

       at Telerik.Windows.Controls.MaskedInput.PreviewInputTextBox.OnTextInput(TextCompositionEventArgs e) in c:\TB\105\WPF_Scrum\Current_HotFix\Sources\Controls\Input\MaskedInput\PreviewInputTextBox.cs:line 55

       at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)

       at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)

       at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)

       at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)

       at System.Windows.Input.InputManager.ProcessStagingArea()

       at System.Windows.Input.TextCompositionManager.UnsafeCompleteComposition(TextComposition composition)

       at System.Windows.Input.TextCompositionManager.PostProcessInput(Object sender, ProcessInputEventArgs e)

       at System.Windows.Input.InputManager.RaiseProcessInputEventHandlers(ProcessInputEventHandler postProcessInput, ProcessInputEventArgs processInputEventArgs)

       at System.Windows.Input.InputManager.ProcessStagingArea()

       at System.Windows.Input.TextCompositionManager.UnsafeStartComposition(TextComposition composition)

       at System.Windows.Input.TextCompositionManager.PostProcessInput(Object sender, ProcessInputEventArgs e)

       at System.Windows.Input.InputManager.RaiseProcessInputEventHandlers(ProcessInputEventHandler postProcessInput, ProcessInputEventArgs processInputEventArgs)

       at System.Windows.Input.InputManager.ProcessStagingArea()

       at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)

       at System.Windows.Interop.HwndKeyboardInputProvider.ProcessTextInputAction(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)

       at System.Windows.Interop.HwndSource.OnPreprocessMessage(Object param)

       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)

       at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)

  InnerException:

            seriesMapping seriesMapping = new SeriesMapping();
             foreach (IGroupDescriptor descriptor in chartGrid.GroupDescriptors)
            {
                seriesMapping.GroupingSettings.GroupDescriptors.Add(new ChartGroupDescriptor(getDataMemberName(descriptor)));
            }
            seriesMapping.ItemMappings.Add(new ItemMapping(lastGrouping , DataPointMember.XCategory));
            seriesMapping.ItemMappings.Add(new ItemMapping(lastGrouping , DataPointMember.LegendLabel));
            ChartAggregateFunction aggFunc = getChartAggregation(lbxFunction);
            mapping = new ItemMapping(lbxSumm.SelectedValue.ToString(), DataPointMember.YValue, aggFunc);
            DataColumn col = dt.Columns[lbxSumm.SelectedValue.ToString()];
            if (col != null) mapping.FieldType = col.DataType;
            seriesMapping.ItemMappings.Add(mapping);
            radChart1.DefaultSeriesDefinition = (ISeriesDefinition)getChartType();
            radChart1.ItemsSource = null;
            radChart1.SeriesMappings.Clear();
            radChart1.DefaultView.ChartLegend.UseAutoGeneratedItems = true;
            radChart1.DefaultSeriesDefinition.LegendDisplayMode = LegendDisplayMode.SeriesLabel; 
            DataTable dtSource = dt;
            radChart1.SeriesMappings.Add(seriesMapping);
            radChart1.ItemsSource = dtSource;