Comment 34 for bug 1292830

This happens to me on my ASUS ZenBook UX32VD with a GeForce GT620M if I plug in an external monitor while using the GeForce card, but not if I plug in the monitor while using the Intel graphics and then switch to the GeForce card afterwards

$ uname -r
3.13.0-35-generic

$ apt list xserver-xorg-video-intel
Listing... Done
xserver-xorg-video-intel/trusty-updates,now 2:2.99.910-0ubuntu1.1 amd64 [installed]

$ apt list compiz nvidia-prime nvidia-331
Listing... Done
compiz/trusty-updates,now 1:0.9.11.2+14.04.20140714-0ubuntu1 all [installed]
nvidia-331/trusty-updates,now 331.38-0ubuntu7.1 amd64 [installed]
nvidia-prime/trusty,now 0.6.2 amd64 [installed,automatic]

$ apt-cache policy nvidia-331-updates
nvidia-331-updates:
  Installed: (none)
  Candidate: 331.38-0ubuntu7.1
  Version table:
     331.38-0ubuntu7.1 0
        500 http://dk.archive.ubuntu.com/ubuntu/ trusty-updates/restricted amd64 Packages
     331.38-0ubuntu7 0
        500 http://dk.archive.ubuntu.com/ubuntu/ trusty/restricted amd64 Packages

$ apt-cache policy compiz
compiz:
  Installed: 1:0.9.11.2+14.04.20140714-0ubuntu1
  Candidate: 1:0.9.11.2+14.04.20140714-0ubuntu1
  Version table:
 *** 1:0.9.11.2+14.04.20140714-0ubuntu1 0
        500 http://dk.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     1:0.9.11+14.04.20140409-0ubuntu1 0
        500 http://dk.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

Btw: +1 for comment #30 :)