Sortedness problems with MultiIndex

[wesm]

Take this example:

arrays = [['bar', 'bar', 'baz', 'baz', 'qux', 'qux', 'foo', 'foo'],
['one', 'two', 'one', 'two', 'one', 'two', 'one', 'two']]
tuples = zip(*arrays)
tuples
index = MultiIndex.from_tuples(tuples)
s = Series(randn(8), index=index)

This does not yield the expected result:

s['qux']

[wesm]

This really should work even though things aren't sorted by the first level