Can't type text into Thesaurus

I'm trying to test out the Contextual Thesaurus.

It works fine on the automatically generated random snippets, but I am unable to enter text into the field (I am able to delete text).

I've just updated the Silverlight plugin, and I'm on Google Chrome.

Any tips for getting this to work? Also, is there an API for the Contextual Thesaurus?

Thanks,
Zack