A customer has sent me this stack trace from an error they received when loading a screen. They have not been able to consistently reproduce the problem. Does anyone have any clue what might be causing a null reference error to be thrown from the internal BinarySearchValues method in the combo control when I call DataSet.AcceptChanges?

Thanks,

 Glenn

-------------STACK TRACE-----------
   at Infragistics.Win.UltraWinGrid.UltraDropDownBase.BinarySearchSortComparer.BinarySearchValues(List`1 rows, Object value)
   at Infragistics.Win.UltraWinGrid.UltraDropDownBase.PerformBinarySearch(Object dataValue, Int32& index, Boolean getValue)
   at Infragistics.Win.UltraWinGrid.UltraDropDownBase.GetTextHelper(Object dataValue, Int32& index)
   at Infragistics.Win.UltraWinGrid.UltraDropDownBase.Infragistics.Win.IValueList.GetText(Object dataValue, Int32& index)
   at Infragistics.Win.UltraWinGrid.UltraCombo.SelectedItemChangeHelper(ComboSelectedItemChangeContext context, Object newData)
   at Infragistics.Win.UltraWinGrid.UltraCombo.FireListChanged()
   at Infragistics.Win.UltraWinGrid.RowsCollection.SyncRows()
   at Infragistics.Win.UltraWinGrid.RowsCollection.EnsureNotDirty()
   at Infragistics.Win.UltraWinGrid.RowsCollection.get_Count()
   at Infragistics.Win.UltraWinGrid.UltraDropDownBase.BuildSortedValueMemberList()
   at Infragistics.Win.UltraWinGrid.UltraDropDownBase.get_CanDoBinarySearch()
   at Infragistics.Win.UltraWinGrid.UltraDropDownBase.GetTextHelper(Object dataValue, Int32& index)
   at Infragistics.Win.UltraWinGrid.UltraDropDownBase.Infragistics.Win.IValueList.GetText(Object dataValue, Int32& index)
   at Infragistics.Win.UltraWinGrid.UltraCombo.SelectedItemChangeHelper(ComboSelectedItemChangeContext context, Object newData)
   at Infragistics.Win.UltraWinGrid.UltraCombo.FireListChanged()
   at Infragistics.Win.UltraWinGrid.RowsCollection.OnListChangedHelper(ListChangedEventArgs e, Boolean calledFromBandListChanged)
   at Infragistics.Win.UltraWinGrid.RowsCollection.OnListChanged(Object sender, ListChangedEventArgs e)
   at System.ComponentModel.ListChangedEventHandler.Invoke(Object sender, ListChangedEventArgs e)
   at System.Windows.Forms.BindingSource.OnListChanged(ListChangedEventArgs e)
   at System.Windows.Forms.BindingSource.InnerList_ListChanged(Object sender, ListChangedEventArgs e)
   at System.Data.DataView.OnListChanged(ListChangedEventArgs e)
   at System.Data.DataView.IndexListChanged(Object sender, ListChangedEventArgs e)
   at System.Data.DataView.IndexListChangedInternal(ListChangedEventArgs e)
   at System.Data.DataViewListener.IndexListChanged(ListChangedEventArgs e)
   at System.Data.Index.<OnListChanged>b__2(DataViewListener listener, ListChangedEventArgs args, Boolean arg2, Boolean arg3)
   at System.Data.Listeners`1.Notify[T1,T2,T3](T1 arg1, T2 arg2, T3 arg3, Action`4 action)
   at System.Data.Index.OnListChanged(ListChangedEventArgs e)
   at System.Data.Index.FireResetEvent()
   at System.Data.DataTable.RestoreIndexEvents(Boolean forceReset)
   at System.Data.DataTable.AcceptChanges()
   at System.Data.DataSet.AcceptChanges()
   at NewDawnTechControls.NdtSnapInSessionController.GetSessionDataInternal(Object sessionParams)
   at System.Threading._ThreadPoolWaitCallback.WaitCallback_Context(Object state)
   at System.Threading.ExecutionContext.runTryCode(Object userData)
   at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallbackInternal(_ThreadPoolWaitCallback tpWaitCallBack)
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback(Object state)