if (fSelectionChangedListeners != null) { fSelectionChangedListeners.add(listener); }
if (fSelectionChangedListeners != null) fSelectionChangedListeners.remove(listener);
	public void removeSelectionChangedListener(ISelectionChangedListener listener) {		if (fSelectionChangedListeners != null) {			fSelectionChangedListeners.add(listener);		}	}	