Comment 22 for bug 1024768

(Second try on this post)

It's probably good for everyone to keep an eye on https://launchpad.net/~xorg-edgers/+archive/ppa . Right now it says:

"July 13th: Mesa currently has problems with unity where the launcher icons are invisible, it's suggested to hold mesa back to the 0529 version, stop using this PPA, or use another session such as gnome or unity-2d until it is fixed."

So people who want to stick with the edgers drivers should try downgrading the mesa packages first. You may still have them on your system, under /var/cache/apt/archives , or you might find them by poking around the ppa. Hope this helps.