NullReferenceException in System.Windows.Forms.TreeView

Question

Hi,

I am getting the following exception, intermittently, when using the TreeView component. Can anyone
share any similar experiences with the TreeView. Can anyone suggest what I can do to further 
track down the source of the error? I am at a loss at how to proceed with debugging this, as
my own classes are not called within this stack trace.

Thanks for any help.
Stephen.

Exception: System.NullReferenceException
Message: Object reference not set to an instance of an object.
Source: System.Windows.Forms
   at System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at System.Windows.Forms.NativeWindow.DefWndProc(Message& m)
   at System.Windows.Forms.Control.DefWndProc(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.TreeView.WndProc(Message& m)
   at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)