I am using an ultrawintree control displaying data in the form of grid i.e. ViewStyle is grid. Now I right click on the header and then left click on any of the cell, it throws an application error. The call stack is as follows:

System.NullReferenceException: Object reference not set to an instance of an object.
   at Infragistics.Win.UltraWinTree.UltraTree.UltraTreeGridBagLayoutDragManager.ColumnRepositionDragEnd(Point clientPoint)
   at Infragistics.Win.UltraWinTree.UltraTree.Infragistics.Win.ISelectionManager.OnDragEnd(Boolean cancelled)
   at Infragistics.Win.SelectionStrategyNone.OnMouseMessage(ISelectableItem item, MouseMessageInfo& msginfo)
   at Infragistics.Win.ControlUIElementBase.ProcessMouseUpHelper(Object sender, MouseEventArgs e)
   at Infragistics.Win.ControlUIElementBase.ProcessMouseUp(Object sender, MouseEventArgs e)
   at System.Windows.Forms.MouseEventHandler.Invoke(Object sender, MouseEventArgs e)
   at System.Windows.Forms.Control.OnMouseUp(MouseEventArgs e)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   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.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)

Please Help!!!!!!