@Override
public void createControl(Composite parent) {
super.createControl(parent);
getTreeViewer().setContentProvider(new OutlinePageContentProvider());
getTreeViewer().setLabelProvider(new DelegatingStyledCellLabelProvider(new NodeLabelProvider()));
getTreeViewer().addSelectionChangedListener(this);
getTreeViewer().addSelectionChangedListener(new ISelectionChangedListener() {
@Override
public void selectionChanged(SelectionChangedEvent event) {
handleSelectionChanged();