treeViewer.setContentProvider(.....);
        treeViewer.setLabelProvider(......);
        treeViewer.setSorter(........);
        treeViewer.setInput(<latest root element>);

        IContentProvider contentProvider = treeViewer.getContentProvider();
        if (contentProvider instanceof NavigatorContentProvider)
        {
            ((NavigatorContentProvider) contentProvider).reset();
        }

        treeViewer.refresh(true);