Firefox crashes after opening HUD

I installed the new WebApps feature and changed a lot of stuff that the installation required. While I was trying it, I noticed that Firefox crashed every time I opened the HUD. I uninstalled the WebApps thing following the instructions in their PPA https://launchpad.net/~webapps/+archive/preview

sudo apt-get install ppa-purge
sudo ppa-purge ppa:webapps/preview

But the problem is still there. I think Unity got updated to a test version but it didn't downgrade to the previous version after uninstalling the ppa (as some other programs did).

Obviously, what I expected to happen was the HUD to work and Firefox not to crash.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.10.0-0ubuntu6
ProcVersionSignature: Ubuntu 3.2.0-26.41-generic 3.2.19
Uname: Linux 3.2.0-26-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu11
Architecture: amd64
CompizPlugins: [core,bailer,detection,composite,opengl,decor,resize,imgpng,compiztoolbox,grid,mousepoll,neg,vpswitch,wall,snap,gnomecompat,move,place,regex,obs,animation,session,expo,workarounds,ezoom,staticswitcher,fade,scale,unityshell,scaleaddon]
Date: Fri Jul 20 15:23:35 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
ProcEnviron:
 TERM=xterm
 PATH=(custom, user)
 LANG=es_ES.UTF-8
 SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)