gtk:window-gravity (object)

object -- a gtk:window widget
gravity -- a gdk:gravity value for the window gravity

The accessor for the gravity slot gets or sets the window gravity of the window. Window gravity defines the meaning of coordinates passed to the gtk:window-move function. See the gtk:window-move function and the gdk:gravity enumeration for more details.

The default window gravity is :north-west which will typically do what you mean.