Changes the active row of combo_box to the one that has an ID equal to
active_id, or unsets the active row if active_id is NULL. Rows having
a NULL ID string cannot be made active by this function.
If the "id-column" property of combo_box is unset or if no
row has the given ID then the function does nothing and returns FALSE.
Changes the active row of combo_box to the one that has an ID equal to active_id, or unsets the active row if active_id is NULL. Rows having a NULL ID string cannot be made active by this function. If the "id-column" property of combo_box is unset or if no row has the given ID then the function does nothing and returns FALSE.