I can not select negative rules in the Access Level area

I recently updated to Membership 3.4.3.1, and I'm using WP 3.5.1 and BuddyPress 1.6.3.

I'm trying to set up access levels and check them, and I can't even click on the rules, or the content.

If I select one of my membership levels, then try to click on "both" for rules, nothing happens.

Does anybody know if there is a bug in Membership right now, or could this be a Java or other issue with my PC?

On our live site using Membership 3.4.2 the boxes work as they should, you click on them and they open, and I can move between positive, negative and both rules.

Thanks,
Ian