I have been using the beta channel for a long time and this issue with my locale ( https://bugzilla.mozilla.org/show_bug.cgi?id=903716 ) is the worst I can remember. I returned to the "release" channel and have no navigation problems, which is not strange because I had none with betas. I believe Mozilla and we all as "supporters" have to address two problems: a) many people keep getting upset after downloading and installing non-working copies from ( http://www.mozilla.org/en-US/firefox/all-beta.html ), and some of them maybe will not test betas anymore; b) many people with locales are not testing this beta and therefore not helping to "refine and polish the next version of Firefox".