By the way, I discovered I had an error when launching with the terminal, I don't know if it is related:
~$ LANGUAGE=en_US.utf8 gnome-system-monitor ** (gnome-system-monitor:7079): WARNING **: SELinux was found but is not enabled. -- Excessive CPU usage by Gnome System Monitor https://bugs.launchpad.net/bugs/93847 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs