code: public void removeSelectionChangedListener(
  			ISelectionChangedListener listener)
  	{
  		if (fOutlineViewer != null)
  		{
  			fOutlineViewer.removeSelectionChangedListener(listener);
  		} else
  		{
  			fSelectionChangedListeners.remove(listener);
  		}
  	}
docs: /*
  @see ISelectionProvider#removeSelectionChangedListener(ISelectionChangedListener )