I see this same behavior without using nitrogen. I simply run a daemon that regenerates the image nautilus is pointing to as the desktop background periodically. After leaving it running overnight, I get the same "Maximum number of clients reached" error. I can continue working for a while by killing nautilus, or chrome, or some other application, but I have to restart X to get back to normal again.
** Also affects: xorg-server (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1045899 Title: Maximum number of clients reached To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1045899/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs