My support subscription has temporarily expired, so I am writing this bug report here.

Several charts, contained in a vertical itemscontrol (and scroll viewer). I think that some of the charts were scrolled off screen.

Move the mouse over a chart and the exception is thrown.

May/may not be relevant, but the charts are in this order... A, B, A, B, A, B, A, B....

All the A charts are synchronised. All the B charts are synchronised. (different channels)

Only synchronising the horzontal zoom and cross hair.

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Stack trace
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    System.ArgumentException: 'NaN' is not a valid value for property 'X1'.
    ----------------------------------------------------------------------
    at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal):
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    at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value):
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    at Infragistics.Controls.SeriesViewerView.UpdateVerticalCrosshair(Double x1, Double y1, Double x2, Double y2):
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    at Infragistics.Controls.SeriesViewer.RenderCrosshairs():
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    at Infragistics.Controls.SeriesViewer.PropertyUpdatedOverride(Object sender, String propertyName, Object oldValue, Object newValue):
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    at Infragistics.Controls.Charts.XamDataChart.PropertyUpdatedOverride(Object sender, String propertyName, Object oldValue, Object newValue):
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    at Infragistics.Controls.SeriesViewer.<.ctor>b__7f(Object o, PropertyUpdatedEventArgs e):
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    at Infragistics.Controls.Charts.PropertyUpdatedEventHandler.Invoke(Object sender, PropertyUpdatedEventArgs e):
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    at Infragistics.Controls.SeriesViewer.RaisePropertyChanged(String name, Object oldValue, Object newValue):
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    at Infragistics.Controls.SeriesViewer.set_CrosshairPoint(Point value):
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    at Infragistics.Controls.Charts.SyncLink.CrosshairNotify(SeriesViewer sender, Point crossHairPoint):
    ----------------------------------------------------------------------
    at Infragistics.Controls.SeriesViewer.CrosshairNotify(Point notificationPoint):
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    at Infragistics.Controls.SeriesViewerView.PlotArea_MouseEnter(Object sender, MouseEventArgs e):
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    at System.Windows.Input.MouseEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget):
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    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.RaiseEvent(RoutedEventArgs e):
    ----------------------------------------------------------------------
    at System.Windows.MouseOverProperty.FireNotifications(UIElement uie, ContentElement ce, UIElement3D uie3D, Boolean oldValue):
    ----------------------------------------------------------------------
    at System.Windows.ReverseInheritProperty.FirePropertyChangeInAncestry(DependencyObject element, Boolean oldValue, DeferredElementTreeState treeState, Action`2 originChangedAction):
    ----------------------------------------------------------------------
    at System.Windows.ReverseInheritProperty.OnOriginValueChanged(DependencyObject oldOrigin, DependencyObject newOrigin, IList`1 otherOrigins, DeferredElementTreeState& oldTreeState, Action`2 originChangedAction):
    ----------------------------------------------------------------------
    at System.Windows.Input.MouseDevice.ChangeMouseOver(IInputElement mouseOver, Int32 timestamp):
    ----------------------------------------------------------------------
    at System.Windows.Input.MouseDevice.PreNotifyInput(Object sender, NotifyInputEventArgs e):
    ----------------------------------------------------------------------
    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):
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    at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o):
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    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):