It sounds like the XFCE window manager has crashed, but I'm not sure. It might be a good idea to follow these steps:
https://wiki.ubuntu.com/Bugs/Responses#Missing_a_crash_report_or_having_a_.crash_attachment ** Summary changed: - Problem with windows + No border around windows, no resizing buttons (max, min, close). Windows cannot be moved or resized. ** Package changed: xorg (Ubuntu) => xfce4 (Ubuntu) -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1819909 Title: No border around windows, no resizing buttons (max, min, close). Windows cannot be moved or resized. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xfce4/+bug/1819909/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
