Applications that interact with the user via windows must present information in a clear manner. Similarly designed windows help the user to understand the interface better. The system requires that an application manage the windows in the interface. That application is called the window manager. The window manager is a specific application that manages the windows in an interface. The window manager follows the same guidelines for input, navigation, selection, and activation as described in this book.
The window manager supports multiple applications, each with one or more primary windows. It also supports secondary windows and associates each secondary window with a primary window or another secondary window.
You can design the window manager to allow users to configure it, as well as other elements, including key bindings, menu contents, and default window controls. The window manager supplies the default settings. Users can toggle between their configured settings and the default settings.