I haven't tested this, but from a comment on the relevant Mozilla ticket that looks to be the case. The workaround from that ticket that we were using no longer works in Fx3.5. Unless they decide to backport the patch to 3.5 (from the post-3.5 trunk), the only workaround is apparently to add in exceptions for every site. We'll update the code so that it will work in versions after 3.5 and add a note to the Known Issues page.