gtk-box-reorder-child (box child position)

box -- a gtk-box container widget
child -- the gtk-widget child widget to move
position -- an integer with the position for child in the list of children of box, starting from 0, if negative, indicates the end of the list

Moves the child widget to a new position in the list of the box children. The list is the children field of the box, and contains both widgets packed :start as well as widgets packed :end, in the order that these widgets were added to the box.

A position of the child widget in the box children list determines where the widget is packed into the box. A child widget at some position in the list will be packed just after all other widgets of the same packing type that appear earlier in the list.