The method CompoundScope.getElements doesn't pass the scope filter to subscopes when scanning members of a given class; look at the code:

@Override
        public Iterable<Symbol> getElements(final Filter<Symbol> sf) {
            return new Iterable<Symbol>() {
                public Iterator<Symbol> iterator() {
                    return new CompoundScopeIterator(subScopes) {
                        Iterator<Symbol> nextIterator(Scope s) {
                            return s.getElements().iterator(); //PROBLEM
                        }
                    };
                }
            };
        }

The problematic line should be:

     return s.getElements(***sf***).iterator(); //PROBLEM