At least for me the problem seems to be related to the file ".nvidia- settings.rc". After deleting it from my home-directory I just now got the window-decorations back after reboot...
-- missing window decorations after reboot https://bugs.launchpad.net/bugs/408764 You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to metacity in ubuntu. -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs