I think this is a bug in xserver-xorg-video-intel since I saw this on 2 machines using the Intel i3-Clarkdale-CPU-integrated graphics. I upgraded the driver package from xserver-xorg-video-intel 2:2.12.0-1ubuntu5.1 to xserver-xorg-video-intel 2:2.13.901-2ubuntu2. This solves the problem for me.
The new package comes from the natty repostitory and can be found here: https://launchpad.net/ubuntu/natty/amd64/xserver-xorg-video-intel/2:2.13.901-2ubuntu2 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/677694 Title: Firefox Crashes X -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs