gdk-window-toplevel (window)

window -- a gdk-window object

The gdk-window toplevel window containing window.

Gets the toplevel window that is an ancestor of the window.

Any window type but :child is considered a toplevel window, as is a :child window that has a root window as parent.

Note that you should use the function gdk-window-effective-toplevel when you want to get to a window's toplevel as seen on screen, because the function gdk-window-toplevel will most likely not do what you expect if there are offscreen windows in the hierarchy.