`Network Manager` GUI Missing in Ubuntu 18.04

I'm totally agree, GNOME 3 Settings network managements features are the very entry-level ATM, comparing to original Network Manager GUI and Applet.

How to enable classic Network Manager GUI for Ubuntu 18.04 Bionic

(For current user.)

Command-line solution:

# Make sure is's installed
sudo apt-get install network-manager network-manager-gnome

# Enable application desktop item
sed 's/^NotShowIn=/#NotShowIn=/g' /usr/share/applications/nm-connection-editor.desktop > ~/.local/share/applications/nm-connection-editor.desktop

# Set applet to auto-start
sed 's/^NotShowIn=/#NotShowIn=/g; s/^NoDisplay=/#NoDisplay=/g' /usr/share/applications/nm-applet.desktop > ~/.config/autostart/nm-applet.desktop