Using the ultraGrid to create a hierarchal tree, we are running into an error. Under uncertain conditions the display when expanding a level, the display blows up with the following error:

 Anybody have a suggestion on what is happening here:  The object does exist.  but we are fetching the data at each expansion so it could be a    timing issue.

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Object reference not set to an instance of an object. (Infragistics2.Win.UltraWinGrid.v7.1)

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Program Location:

   at Infragistics.Win.UltraWinGrid.UltraGridColumn.GetCachedCellAppearance(Boolean selected, AppearanceData& appData, ResolveAppearanceContext& context)
   at Infragistics.Win.UltraWinGrid.UltraGridRow.ResolveCellAppearance(UltraGridColumn column, AppearanceData& appData, AppearancePropFlags& requestedProps, Boolean cellAppearanceOnly, Boolean forceSelected, ForceActive forceActive, Boolean isMergedCell, Boolean hotTrackingCell, Boolean hotTrackingRow)
   at Infragistics.Win.UltraWinGrid.UltraGridLayout.ResolvedCachedCellAppearance(UltraGridRow row, UltraGridColumn column, AppearanceData& appData, AppearancePropFlags& flags, Boolean hotTrackingCell, Boolean hotTrackingRow)
   at Infragistics.Win.UltraWinGrid.CellUIElementBase.InternalInitAppearance(AppearanceData& appearance, AppearancePropFlags& requestedProps)
   at Infragistics.Win.UltraWinGrid.CellUIElementBase.InitAppearance(AppearanceData& appearance, AppearancePropFlags& requestedProps)
   at Infragistics.Win.UIElement.InitializeDrawAppearance(AppearanceData& defaultAppearance, AppearanceData& appearance)
   at Infragistics.Win.UIElement.DrawElement(UIElementDrawParams& defaultDrawParams)
   at Infragistics.Win.UIElement.DrawChildElements(UIElementDrawParams& drawParams)
   at Infragistics.Win.UIElement.DrawElement(UIElementDrawParams& defaultDrawParams)
   at Infragistics.Win.UIElement.DrawChildElements(UIElementDrawParams& drawParams)
   at Infragistics.Win.UIElement.DrawElement(UIElementDrawParams& defaultDrawParams)
   at Infragistics.Win.UIElement.DrawChildElements(UIElementDrawParams& drawParams)
   at Infragistics.Win.UIElement.DrawElement(UIElementDrawParams& defaultDrawParams)
   at Infragistics.Win.UIElement.DrawChildElements(UIElementDrawParams& drawParams)
   at Infragistics.Win.UIElement.DrawElement(UIElementDrawParams& defaultDrawParams)
   at Infragistics.Win.UIElement.DrawChildElements(UIElementDrawParams& drawParams)
   at Infragistics.Win.UIElement.DrawElement(UIElementDrawParams& defaultDrawParams)
   at Infragistics.Win.UIElement.DrawHelper(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode, Boolean clipText, Boolean forceDrawAsFocused, Boolean preventAlphaBlendGraphics)
   at Infragistics.Win.UIElement.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode, Boolean forceDrawAsFocused, Boolean preventAlphaBlendGraphics)
   at Infragistics.Win.ControlUIElementBase.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode, Size elementSize, Boolean preventAlphaBlendGraphics)
   at Infragistics.Win.ControlUIElementBase.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode, Size elementSize)
   at Infragistics.Win.ControlUIElementBase.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode)
   at Infragistics.Win.UltraWinGrid.UltraGridUIElement.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode)
   at Infragistics.Win.UltraControlBase.OnPaint(PaintEventArgs pe)
   at Infragistics.Win.UltraWinGrid.UltraGrid.OnPaint(PaintEventArgs pe)
   at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer, Boolean disposeEventArgs)
   at System.Windows.Forms.Control.WmPaint(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)