// Return no resize handles
@Override
public HandleEnumeration handles() {
List<NullHandle> handles = new ArrayList<NullHandle>();
handles.add(new NullHandle(this, RelativeLocator.southEast()));
handles.add(new NullHandle(this, RelativeLocator.southWest()));
handles.add(new NullHandle(this, RelativeLocator.northEast()));
handles.add(new NullHandle(this, RelativeLocator.northWest()));
return new HandleEnumerator(handles);
}