*/
public EditableTreeGridPage() {
List<IGridColumn> columns = new ArrayList<IGridColumn>();
columns.add(new SubmitCancelColumn("edit", new Model("Edit")));
columns.add(new EditablePropertyTreeColumn(new Model("Property 1"), "userObject.property1"));
columns.add(new EditablePropertyColumn(new Model("Property 2"), "userObject.property2"));
columns.add(new EditablePropertyColumn(new Model("Property 3"), "userObject.property3"));
columns.add(new EditablePropertyColumn(new Model("Property 4"), "userObject.property4"));
columns.add(new EditablePropertyColumn(new Model("Property 5"), "userObject.property5"));
columns.add(new EditablePropertyColumn(new Model("Property 6"), "userObject.property6"));