Selects a range of characters in the label, if the label is selectable.
See gtk_label_set_selectable(). If the label is not selectable,
this function has no effect. If @start_offset or
@end_offset are -1, then the end of the label will be substituted.
Selects a range of characters in the label, if the label is selectable. See gtk_label_set_selectable(). If the label is not selectable, this function has no effect. If @start_offset or @end_offset are -1, then the end of the label will be substituted.