I'm facing issues recently with Ubuntu 18 after deleting unused kernels by
sudo apt-get autoremove --purgetaskbar is not appearing.
Tapping Super shows taskbar.
01 Answer
Make sure Ubuntu Dock is installed by running the following command in Terminal
sudo apt install gnome-shell-extension-ubuntu-dockand then re-login.
Note that if you enable the 'Auto-hide the Dock' option in Ubuntu Dock settings, then the dock would be hidden until mouseover to dodge windows. To make the dock visible all the time launch Settings application and in the 'Dock' section disable 'Auto-hide the Dock'.