Thanks for all that. Unfortunately I can't find any previous reports of this exact bug. Though I expect this bug does not exist in Ubuntu 20.04 since the offending tweener code was removed there.
** Summary changed: - System hangs, syslog filled with `org.gnome.Shell.desktop` reports + System hangs, syslog filled with: Object St.BoxLayout (...), has been already deallocated - impossible to access it. Called from ubuntu-d...@ubuntu.com/docking.js:184 from tweener.js:322 ** Changed in: gnome-shell (Ubuntu) Importance: Undecided => Medium ** Changed in: gnome-shell (Ubuntu) Status: Incomplete => New ** Tags added: performance ** Package changed: gnome-shell (Ubuntu) => gnome-shell-extension- ubuntu-dock (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1887235 Title: System hangs, syslog filled with: Object St.BoxLayout (...), has been already deallocated - impossible to access it. Called from ubuntu- d...@ubuntu.com/docking.js:184 from tweener.js:322 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell-extension-ubuntu-dock/+bug/1887235/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs