I have a panel in a Form that uses Toolbars.I that Panel I draw and "move" objets (be redrawing)

Everything worked fine until I stardet to Use

ThreadPool.QueueUserWorkItem( _
          New Threading.WaitCallback(

to make asynchronous call for some time consuming methods. Now, I have the follwing:

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An application UnhandledException were thrown.

The application will now terminate.

'Object reference not set to an instance of an object.'



StackTrace:

   at Infragistics.Win.UltraWinToolbars.UltraToolbarBase.ToolbarToolRow.InternalAddTool(ToolBase tool, Size toolSize, Boolean needsHorizontalSeparator)

   at Infragistics.Win.UltraWinToolbars.UltraToolbarBase.ToolGroup.CalculateMetrics(Int32 maxWidth)

   at Infragistics.Win.UltraWinToolbars.UltraToolbarBase.ToolbarMetrics.CalculateFloatingMetricsHelper(ToolGroup[] toolGroups, Int32 maxWidth)

   at Infragistics.Win.UltraWinToolbars.UltraToolbarBase.ToolbarMetrics.CalculateFloatingMetrics(Size cachedSize, Size delta)

   at Infragistics.Win.UltraWinToolbars.UltraToolbarBase.GetMetrics(Size cachedSize, Size delta)

   at Infragistics.Win.UltraWinToolbars.UltraToolbarBase.ToolAreaInformation.FromToolbar(UltraToolbarBase toolbar, Rectangle overallArea)

   at Infragistics.Win.UltraWinToolbars.ToolbarUIElement.PositionChildElements()

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

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

   at Infragistics.Win.UIElement.DrawHelper(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode, Boolean clipText, Boolean forceDrawAsFocused)

   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.UltraControlBase.OnPaint(PaintEventArgs pe)

   at Infragistics.Win.UltraWinToolbars.UltraToolbarsDockArea.OnPaint(PaintEventArgs pe)

   at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer)

   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)
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OK  
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Then , the toolboxex became white + redCrossed.

As you can see the exception is not even handled, but intercepted OnUnhandledApplication on the application level...