My magic mouse won't swipe back or forward in Firefox. I updated to Mavericks the day after it was made available to the public and had no issues with the mouse until Firefox updated to 25.0.X several weeks ago. Now, swiping left/right on the mouse acts more like "reload" instead of back/forward. It works fine in Safari.
I've used Better Touch Tool for the past year with no issues. The only custom gesture I use is a single 3-finger tap to automatically scroll to the top of a page. That's it. Installing Mavericks didn't uncheck any of my mouse settings in the System Preferences like other users have noted. I unchecked the "Swipe Between Pages" option in the System Preferences and created 2 new gestures in BTT: CMD+[ and CMD+] for forward and backward. It sort of works. I can now use a single finger to swipe forward/back in Firefox (or any other browser), but it's too flakey. Sometimes it's like I only have to bring my finger near the mouse and the browser page will jump backwards without warning - really really annoying when entering information into a form on a website. Yes, I have lowered the sensitivity in the BTT settings.
I literally just installed the latest BTT 0.992 hoping it would fix it. It didn't. If I disable BTT, swipe goes back to not working at all whether the option "Swipe Between Pages" is set or not. Fix. This. Bug. Apple. I've been a huge fan of the magic mouse since buying my first iMac a year ago... and over the past 2 weeks you have made me want to smash this thing into oblivion - the mouse, not the iMac. 😝