System.NullReferenceException: Object reference not set to an instance of an object.

   at Infragistics.Win.UltraWinGrid.UltraGridBand.get_CellPaddingResolved()

   at Infragistics.Win.UltraWinGrid.UltraGridColumn.get_CellSizeDefault()

   at Infragistics.Win.UltraWinGrid.UltraGridColumn.get_Width()

   at Infragistics.Win.UltraWinGrid.ColumnHeader.get_Extent()

   at Infragistics.Win.UltraWinGrid.ViewStyleBase.GetHeaderExtent_AutoFitExtendLastColumn_NonRowLayout(HeaderBase header)

   at Infragistics.Win.UltraWinGrid.ViewStyleBase.AddBandHeaders(ColScrollRegion csr, UltraGridBand band)

   at Infragistics.Win.UltraWinGrid.ViewStyleSingle.RecreateHeaderList(ColScrollRegion csr)

   at Infragistics.Win.UltraWinGrid.ColScrollRegion.RegenerateVisibleHeaders()

   at Infragistics.Win.UltraWinGrid.DataAreaUIElement.VerifyChildElements(ControlUIElementBase controlElement, Boolean recursive)

   at Infragistics.Win.UIElement.VerifyChildElements(ControlUIElementBase controlElement, Boolean recursive)

   at Infragistics.Win.UltraWinGrid.UltraGridUIElement.VerifyChildElements(ControlUIElementBase controlElement, Boolean recursive)

   at Infragistics.Win.UIElement.VerifyChildElements(Boolean recursive)

   at Infragistics.Win.ControlUIElementBase.VerifyIfElementsChanged(Boolean verify, Boolean syncMouseEntered)

   at Infragistics.Win.ControlUIElementBase.ProcessMouseMoveHelper(Object sender, MouseEventArgs e)

   at Infragistics.Win.ControlUIElementBase.ProcessMouseMove(Object sender, MouseEventArgs e)

   at Infragistics.Win.Utilities.ProcessEvent(Control control, ProcessEvent eventToProcess, EventArgs e)

   at Infragistics.Win.UltraControlBase.OnMouseMove(MouseEventArgs e)

   at System.Windows.Forms.Control.WmMouseMove(Message& m)

   at System.Windows.Forms.Control.WndProc(Message& m)

   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Ultimately, a 'red X' shows. I've been trying to track down a similar (hopefully the same) issue that some users have been seeing every few days.

The EL_ExtFeatures.EasyGrid.UltraEasyGrid.OnPaint override simply logs whether it's called from the "wrong" thread (specifically, the 'right' thread is the one from which the parent form's instance was created). However, this code is being called on the correct thread. InvokeRequired also returns 'false'.

The PaintEventArgs contain an empty rectangle (size and position 0). Subsequent drawing calls fail in GetHdc:

at System.Drawing.Graphics.GetHdc()
at Infragistics.Win.UltraWinGrid.ExcelExport.UltraGridExcelExporter..ctor()
at Infragistics.Win.UltraWinGrid.ExcelExport.UltraGridExcelExporter..ctor(IContainer container)

[..]

at Infragistics.Win.UltraWinTabControl.UltraTabControlBase.OnSelectedTabChanging(SelectedTabChangingEventArgs e)
at Infragistics.Win.UltraWinTabControl.UltraTabControlBase.RaiseEvent(UltraTabControlEventId id, EventArgs e)
at Infragistics.Win.UltraWinTabControl.UltraTabControlBase.OnManagerSelectedTabItemChanging(Object sender, SelectedTabItemChangingEventArgs e)
at Infragistics.Win.UltraWinTabs.TabManager.set_SelectedTabItem(ITabItem value)
at Infragistics.Win.UltraWinTabControl.UltraTabControlBase.PerformDelayedInitialize()
at Infragistics.Win.UltraWinTabControl.UltraTabControlBase.OnCreateControl()
at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
at System.Windows.Forms.Control.CreateControl()
at System.Windows.Forms.Control.SetVisibleCore(Boolean value)

I.e., GDI is unhappy about something. However, I'm having a hard time tracking down where this problem first occurs. Any pointers? Is it a threading problem at all?