I can confirm this on my system. any way to recover from this without restarting the X server?
Installation from 12.04 64bit cd. Running in gnome classic (no effects). Gnome Force Quit applet on gnome-panel. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-panel in Ubuntu. https://bugs.launchpad.net/bugs/1006490 Title: Gnome Classic 12.04 panel applet “Force Quit” locks up system, hardware reboot to recover Status in “gnome-panel” package in Ubuntu: Confirmed Bug description: Trying to kill a hung application using the Gnome panel applet causes 12.04 Gnome Classic desktop to hang. No console, no response to muse action (except movement), no keyboard response. Requires hardware reset to recover. ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: gnome-panel 1:3.4.1-0ubuntu1 ProcVersionSignature: Ubuntu 3.2.0-24.39-generic 3.2.16 Uname: Linux 3.2.0-24-generic x86_64 NonfreeKernelModules: nvidia ApportVersion: 2.0.1-0ubuntu7 Architecture: amd64 Date: Wed May 30 08:54:08 2012 InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429) ProcEnviron: TERM=xterm PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: gnome-panel UpgradeStatus: Upgraded to precise on 2012-05-25 (4 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-panel/+bug/1006490/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp