The first time the tree is loaded and I press the control key , nothing happens. But if I select a cell and then refresh the view such that now no cell is selected. And now if I press the control key, it throws an application error. Any idea, why this happens and any solution to this? Following is the stack trace with the exception-

System.ArgumentNullException: Key cannot be null.
Parameter name: key
   at System.Collections.Hashtable.ContainsKey(Object key)
   at System.Collections.Hashtable.Contains(Object key)
   at Infragistics.Win.UltraWinTree.CellNavigationManager.Process()
   at Infragistics.Win.UltraWinTree.CellNavigator.get_ActiveCellPosition()
   at Infragistics.Win.UltraWinTree.UltraTree.get_CurrentState()
   at Infragistics.Win.UltraWinTree.UltraTree.IsInputKey(Keys keyData)
   at System.Windows.Forms.Control.PreProcessMessage(Message& msg)
   at System.Windows.Forms.Control.PreProcessControlMessageInternal(Control target, Message& msg)