display = Display.getDefault();
viewerObservable = new WritableValue(SWTObservables.getRealm(display));
viewerUpdater = null;
elementSetFactory = new IObservableFactory() {
public IObservable createObservable(Object target) {
IElementComparer comparer = null;
if (target instanceof StructuredViewer)
comparer = ((StructuredViewer) target).getComparer();
return ObservableViewerElementSet.withComparer(SWTObservables