SciChart 3.1 exception - scichart

Question

A bit of a long-shot given that I'm using such an old version (3.1.0.4759). Users have recently started reporting the exception below when zooming on one of my application's charts. It's a bit of a pain as it can't be handled, so the whole app crashes.
It's very, very intermittent, and I've not been able to repro. The chart series does get cleared down and repopulated once a second, so the intermittent nature could be explained by (say) zooming at that specific moment in time. Having said this, I have a lot of charts throughout my app, many of which are continuously plotting, and all using the same chart modifiers, but have never noticed this problem before.
Just wondering if any of the ABT guys can shed any light on this! TIA.
System.NullReferenceException: Object reference not set to an instance of an object.
at Abt.Controls.SciChart.RangeFactory.NewWithMinMax(IRange originalRange, IComparable min, IComparable max)
at Abt.Controls.SciChart.Wpf.PcitureHelper.Zoom(IRange initialRange, Double fromCoord, Double toCoord)
at Abt.Controls.SciChart.ChartModifiers.RubberBandXyZoomModifier.UpdateOutline(IAxis firstFont, Double currentValues, Double currentId)
at Abt.Controls.SciChart.ChartModifiers.RubberBandXyZoomModifier.UpdateOutline(IAxis firstFont, Rect currentValues)
at Abt.Controls.SciChart.ChartModifiers.RubberBandXyZoomModifier.OpenDatabase(Point firstFont, Point currentValues)
at Abt.Controls.SciChart.ChartModifiers.RubberBandXyZoomModifier.OnModifierMouseUp(ModifierMouseArgs e)
at Abt.Controls.SciChart.ChartModifiers.ModifierGroup.UpdateOutline(Action2 firstFont, ModifierEventArgsBase currentValues)
at Abt.Controls.SciChart.Common.Extensions.EnumerableExtensions.CopyBuilder[firstFont](IEnumerable`1 firstFont, Action1 currentValues)
at Abt.Controls.SciChart.Utility.Mouse.MouseManager.QueueInvoker.JoinControl(Object firstFont, MouseButtonEventArgs currentValues)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
at System.Windows.UIElement.OnMouseUpThunk(Object sender, MouseButtonEventArgs e)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
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.InputManager.ProcessInput(InputEventArgs input)
at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
at System.Windows.Application.RunDispatcher(Object ignore)
at System.Windows.Application.RunInternal(Window window)

Answer 1

It looks like you got a NullReferenceException inside RangeFactory.NewWithMinMax
and also looks like you've customised the source-code, as the methods
at Abt.Controls.SciChart.Wpf.PcitureHelper.Zoom(IRange initialRange, Double fromCoord, Double toCoord)
at Abt.Controls.SciChart.ChartModifiers.RubberBandXyZoomModifier.UpdateOutline(IAxis firstFont, Double currentValues, Double currentId)
at Abt.Controls.SciChart.ChartModifiers.RubberBandXyZoomModifier.UpdateOutline(IAxis firstFont, Rect currentValues).
at Abt.Controls.SciChart.ChartModifiers.RubberBandXyZoomModifier.OpenDatabase
are not part of the SciChart codebase.
So I'd guess that the problem lies in those methods passing invalid values to RangeFactory.
BTW the SciChart team would also tell you that v3 is pretty out of date and to ensure stability, to get up to date. That and if you get problems like this in an old version, especially in customised source-code, they can't help!