gtk-combo-box-text-insert (combo position id text)

combo -- a gtk-combo-box-text widget
position -- an integer with an index to insert text
id -- a string ID for this value, or nil
text -- a string with the text

Inserts text at the given position in the list of strings stored in the combo box. If the ID is non-nil then it is used as the ID of the row. See the id-column property.

If position is negative then the text is appended.