gdk-window-group (window)

window -- a toplevel gdk-window object
leader -- group leader gdk-window object, or nil to restore the default group leader window

The group leader window for window.

The function gdk-window-group returns the group leader window for window. The function (setf gdk-window-group) sets the group leader window for window.

By default, GDK sets the group leader for all toplevel windows to a global window implicitly created by GDK. With this function you can override this default.

The group leader window allows the window manager to distinguish all windows that belong to a single application. It may for example allow users to minimize/unminimize all windows belonging to an application at once. You should only set a non-default group window if your application pretends to be multiple applications.