gtk:window-transient-for (object)

object -- a gtk:window widget
parent -- a gtk:window parent window, or nil

The accessor for the transient-for slot of the gtk:window class gets or sets the transient parent for the window. Dialog windows should be set transient for the main application window they were spawned from. This allows window managers to, for example, keep the dialog on top of the main window, or center the dialog over the main window.

Passing nil for the parent argument unsets the current transient window.

On Windows, this function puts the child window on top of the parent, much as the window manager would have done on X11.