pydata/pandas — pull request #7937 by toobaz (2014-08-05 09:25:06+00:00)
Title: DOC: mention that stack/unstack implicicly sort

It took me a while to discover what was causing this TypeError... I guess this can be useful to other people.

(Yes, I know there is a note somewhere warning users that some operations depend on the index being sorted, but maybe this is a sligthly different case, since the operations do work after all, the problem is they do something more than what is documented)