generic_dataset::set_undrawn

Source: dataset/generic/generic_dataset__set_undrawn.pro

 generic_dataset::set_undrawn
        Clear the drawn flag of a dataset.

 Usage:
        dsref -> set_undrawn

 Notes:
        This is needed because the the drawn flag needs to be cleared
        from outside (e.g. when the ds ceases to be current).

 History:
        Original: 6/6/00; SJT