fViewer.setSorter(null);
fViewer.setSorter(fSourcePositonSorter);
	private void valueChanged(final boolean on, boolean store) {		setChecked(on);		BusyIndicator.showWhile(fViewer.getControl().getDisplay(), new Runnable() {			public void run() {				if (on)					fViewer.setSorter(fSorter);				else					fViewer.setSorter(null);			}		});				if (store)			JavaPlugin.getDefault().getPreferenceStore().setValue(fPreferenceKey, on);	}