gtk:combo-box-wrap-width (object)

object -- a gtk:combo-box widget
width -- an integer for the preferred number of columns

The accessor for the wrap-width slot gets or sets the wrap width which is used to determine the number of columns for the popup menu. If the wrap width is larger than 1, the combo box is in table mode. The wrap width is basically the preferred number of columns when you want the popup to be layed out in a table.