I think this is due to the recent changes to the formatting of the 10k tools (rather than me upgrading to Firefox 6.0):
(I've grayed out the questions and names to protect the innocent. Obviously, that's not how the page actually appears.)
I know it's not an answer but I got the same problem too, although on just one of the flags, the other two are fine. I'm using Chrome.
This problem doesn't exist anymore as this part of the 10k tools has been moved to the review queue since then.