Still borked as of yesterday - can't map my extra mouse buttons, as I once could. Used to use the left-outside mouse button for "always run" but now have to hold down the darn "W" button.
Don't deep-six a function many of us found useful!
So this seems to be a problem only for the Mac OS client. My middle mouse button hasn't worked for a week or so in the Mac client, but I booted my Mac to Windows 8.1 today, for the half-dozen or so daily system updates , and it worked just fine. I've tested two separate devices (Razer Naga and Logitech VX Nano) with the same results. As said previously, let's hope it's fixed in next week's update!
May not have anything to do with the mac mouse problem but this is
From today's patch notes:
Fixed an issue where you could not bind any functions to mouse buttons 4 and 5 on the Razer Naga and Logitech Wireless Mice.