This seems like a duplicate of #1716982, but maybe it's a regression after that was fixed. Anyway, commenter ernstp identifies the cause in comment #12 [1]:
> Is it some global variable name conflict between the two extensions? "dockManager" perhaps? You can edit /usr/share/gnome-shell/extensions/ubuntu- d...@ubuntu.com/extension.js to check for a null dockManager in the disable() function. That is, change dockManager.destroy() to if (dockManager != null) { dockManager.destroy(); } and the dock disappears when the screen is locked, as expected. I'm guessing the problem is that Dash To Dock sets dockManager to null after calling destroy(), and then Ubuntu Dock throws a TypeError when it tries to do the same, so Ubuntu Dock never reaches the ExtensionSystem.disconnect() call. [1] https://bugs.launchpad.net/ubuntu/+source/gnome-shell-extension- ubuntu-dock/+bug/1716982/comments/12 -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1769383 Title: Ubuntu dock/launcher is shown on the lock screen Status in gnome-shell package in Ubuntu: Incomplete Status in gnome-shell-extension-ubuntu-dock package in Ubuntu: Incomplete Bug description: After an update from ubuntu 16.04 to 18.04 the dock is aviable on the lockscreen after user login. I did not configure this knowingly. Also i can start every application which is available on the dock. Settings, virtual box, visualstudio code and so on. After the update to 18.04 i just configure the screen frequency to 144Hz and the night mode on. And attach the dock on bottom. I later undid these customizations back to configuration before, but the dock is stil aviable on lockscreen. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: gnome-settings-daemon 3.28.1-0ubuntu1 ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17 Uname: Linux 4.15.0-20-generic x86_64 NonfreeKernelModules: nvidia_modeset nvidia ApportVersion: 2.20.9-0ubuntu7 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Sat May 5 18:30:16 2018 InstallationDate: Installed on 2018-04-08 (27 days ago) InstallationMedia: Ubuntu 16.04.4 LTS "Xenial Xerus" - Release amd64 (20180228) ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=de_DE.UTF-8 SHELL=/bin/bash SourcePackage: gnome-settings-daemon UpgradeStatus: Upgraded to bionic on 2018-05-01 (3 days ago) --- ApportVersion: 2.20.9-0ubuntu7 Architecture: amd64 CurrentDesktop: ubuntu:GNOME DistroRelease: Ubuntu 18.04 InstallationDate: Installed on 2018-04-08 (27 days ago) InstallationMedia: Ubuntu 16.04.4 LTS "Xenial Xerus" - Release amd64 (20180228) NonfreeKernelModules: nvidia_modeset nvidia Package: gnome-shell-extension-ubuntu-dock 0.9.1 PackageArchitecture: all ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=de_DE.UTF-8 SHELL=/bin/bash ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17 Tags: bionic Uname: Linux 4.15.0-20-generic x86_64 UpgradeStatus: Upgraded to bionic on 2018-05-01 (4 days ago) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo _MarkForUpload: True To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1769383/+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