Unstack MultiIndex vs consecutive unstack
Hello,

If I try to unstack using multiIndex I got some groups divided. However, if I tried to do it by successive unstacking they are correctly grouped.  Please see image below

![image](https://cloud.githubusercontent.com/assets/5657134/8312620/b044c562-19ab-11e5-8f88-f338efdb4ae8.png)

I believe this is due to the fact that the first rows don't have n=3 for "actor" and the corresponding column is added only when it appears in a posterior row. Please note this issue is more related with presentation than performance as both operations yield the same results in subsequent processing (e.g. plotting).

Best!
