The Window Manager The window manager is an X client that gets special treatment from the X server, and receives special event types related to window management. For example, when a client asks the X server to draw a new top-level window, the server first notifies the window manager of that event, allowing it to override the new window's location, and even to re-parent the new window, so it will be drawn inside a window controlled by the window manager. This allows the window manager to drawn borders and title bars around top-level windows. Only one window manager may register with a single X server's screen at a given time.