I have what I assume is the same problem. This only happens on 2 of my 3 machines that run Ubuntu 13.10. Both of these use the Nvidia proprientary driver. The one is a GTX 560 while the other is a GTX610M. I've attached a picture of what it looks like when it freezes. The mouse pointer sill moves but there is no response to input. I can use ctrl- alt-f1 to switch to a terminal though and restarting lightdm restores my computer to a working state.
** Attachment added: "IMG_20140204_133427.jpg" https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1265065/+attachment/3969633/+files/IMG_20140204_133427.jpg -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1265065 Title: Desktop freeze while drag-maximizing window To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1265065/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs