Comment 8 for bug 1263458

I have the solution for this bug !

1):

- In fact, the nvidia-331 driver erase the intel's driver configuration's files, that's the cause of "GLX extension missing on screen 0" and the unity's bug.

2)
- So we need to install nvidia-prime and nvidia-331. Don't log out !!!!

3)
- run terminal and execute : "sudo apt-get install --reinstall libgl1-mesa-glx"
this commande reinstall the configuration of intel's HD4000 driver.

4) - Then reboot your computer

- with this command, intel's driver seems to be correctly configured, unity is running, kde too, openglx is working and I can switch between this two cards, the discrete nvidia-card is perfectly working, and nvidia-prime too.