When clicking on a select the options renders really small and away from the select making it really hard to use and see. I have attached a screenshot of what it looks like.

Hmm, I don't see those UI elements when I visit that page - I guess it requires a login before it presents them? Selection appears to be fine for me (could you confirm?) on other pages (e.g. bugzilla) that use popups/combo-boxes, so it seems like there must be something different about how that page is implemented. A simplified testcase that demonstrates the problem would be awesome.

David, please test with a current mozilla-central nightly (like today's) ... if that's not what you're already doing. http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/

It appears to be working now. Setting to resolved in case someone else can get it and repro it