The Hierarchical Delta debugging Input events can be grouped into levels of sessions lew ma Delete mail list from list compose vew mal ma select Input select subject input body click send receiver attachment click add browse to select file attachment directoryThe Hierarchical Delta Debugging 14 14 Start Gmail view mail list vew mail compose mail select receiver input subject input body select attachment click add attachment browse to directory select file click send Delete mail from list Input events can be grouped into levels of sessions