Or alternatively, you can use the GNOME Tweak Tool to enable the minimize window button. This could need some getting used to at first. By default, windows cannot be minimized in GNOME Shell, as the use of Activities Overview and Workspaces are supposed to replace that.For more information on how to install these extensions, see the answers to this question. Have a look at GNOME Shell Extensions website to see the available ones. Extensions is a powerful feature that enables you to extend the functionality and interface of GNOME Shell.The Notifications system is designed to help you quickly respond to notifications in place or to return to them at a convenient time.The Activities Overview provides an easy way to view all your open windows, drag windows between workspaces, search for applications, and more.Uses Mutter instead of Compiz for the window manager.
It is the default interface used by the officially-supported Ubuntu GNOME flavor, and is the default interface for the main Ubuntu flavor since 17.10 instead of Unity.
GNOME Shell is the 'official' shell developed for GNOME 3 by the GNOME project. GNOME Shell's Application Overview on Ubuntu GNOME 16.04LTS with GNOME 3.18
