When I hover over the column header of my XamGrid I get an exception (included below).  This happens when I do something as simple as <ig:XamGrid ItemsSource={Binding MyItems} /> and let it auto-generate the columns. MyItems is just a BindingList<T> where T is an object with 10 fields, a mix of strings and integers.

The grid is hosted in WPF control which is being hosted on a Winforms form.

Any ideas what might be causing this?

Message : Value cannot be null.
Parameter name: otherVisual
Source : PresentationCore
Help link : 
ParamName : otherVisual
Data : System.Collections.ListDictionaryInternal
TargetSite : System.Windows.DependencyObject FindCommonVisualAncestor(System.Windows.DependencyObject)
Stack Trace :    at System.Windows.Media.Visual.FindCommonVisualAncestor(DependencyObject otherVisual)
   at System.Windows.Media.Visual.TransformToVisual(Visual visual)
   at Infragistics.Controls.Grids.Primitives.HeaderCellControl.GetBoundsOfElement(FrameworkElement element, UIElement relativeElement)
   at Infragistics.Controls.Grids.Primitives.CellControlBase.DetermineCursor(MouseEventArgs e)
   at Infragistics.Controls.Grids.Primitives.CellControlBase.OnMouseMoveColumnResizing(MouseEventArgs e)
   at Infragistics.Controls.Grids.Primitives.CellControlBase.OnMouseMove(MouseEventArgs e)
   at System.Windows.UIElement.OnMouseMoveThunk(Object sender, MouseEventArgs e)
   at System.Windows.Input.MouseEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
   at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   at System.Windows.RouteItem.InvokeHandler(RoutedEventArgs routedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.EventRoute.InvokeHandlers(Object source, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
   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)
   ...