gtk:text-view-add-overlay (view child xpos ypos)

view -- a gtk:text-view widget
child -- a gtk:widget child widget
xpos -- an integer with the x position of child in window coordinates
ypos -- an integer with the y position of child in window coordinates

Adds child at a fixed coordinate in the text window of the gtk:text-view widget. The xpos and ypos arguments must be in buffer coordinates. See the gtk:text-view-iter-location function to convert to buffer coordinates.

The child widget will scroll with the text view. If instead you want a widget that will not move with the text view contents see the gtk:overlay widget.