stages greyed out in extensive form

After loading in a strategic form game (in the screenshot below, nonoisebagwell.xml) and moving to the extensive form, the stages are greyed out and only the tree stage options are available.

![screen shot 2014-03-03 at 17 29 42](https://f.cloud.github.com/assets/743139/2312240/7646c506-a2f9-11e3-8636-444916211612.png)
