final TableTree<Foo> tabletree = new DefaultTableTree<Foo>("tabletree", columns(),
provider, Integer.MAX_VALUE);
// reuse items or drop following expansion will fail due to new
// markup ids
tabletree.setItemReuseStrategy(new ReuseIfModelsEqualStrategy());
tabletree.add(new DragSource()
{
@Override
public Set<Operation> getOperations()
{
return dragOperations();