private void upgradeEditorTreeModel(ICourse course) {
// EDITOR: get all course nodes
CourseEditorTreeModel cT = course.getEditorTreeModel();
TreeNode rootNode = cT.getRootNode();
final Set<String> allSubTreeids = new HashSet<String>();
TreeVisitor tv = new TreeVisitor(new Visitor() {
public void visit(INode node) {
allSubTreeids.add(node.getIdent());
}
}, rootNode, true);
tv.visitAll();