Comment 2 for bug 575160

I've marked Bug #576082 as a duplicate of this report.

Just checked ~/.xsession-errors.old and found:

The program 'seamonkey-2.0-bin' received an X Window System error.
This probably reflects a bug in the program.
The error was 'RenderBadPicture (invalid Picture parameter)'.
  (Details: serial 4062166 error_code 173 request_code 152 minor_code 7)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)
deliver mode: 0

$ apt-cache policy xulrunner-1.9.2
xulrunner-1.9.2:
  Installed: 1.9.2.3+nobinonly-0ubuntu2
  Candidate: 1.9.2.3+nobinonly-0ubuntu2
  Version table:
 *** 1.9.2.3+nobinonly-0ubuntu2 0
        500 http://archive.ubuntu.com/ubuntu/ lucid/main Packages
        100 /var/lib/dpkg/status