viewer = getTreeViewer();
setContentProvider();
viewer.setLabelProvider(new DroolsLabelProvider());
viewer.setSorter(new DroolsTreeSorter());
viewer.setInput(ruleSet);
FilterActionGroup filterActionGroup = new FilterActionGroup(
viewer, "org.drools.eclipse.editors.outline.RuleContentOutlinePage");
filterActionGroup.fillActionBars(getSite().getActionBars());
update();
// add the listener for navigation of the rule document.
super.addSelectionChangedListener(new ISelectionChangedListener() {
public void selectionChanged(SelectionChangedEvent event) {