I'm not at home yet (still goofing off at work), so I haven't had the chance to hunt down the "dominant chord options" in BIAB. But I found this blurb in the new-features section on page 26 of the 2009.5 manual:

"Better playing on the 'V' chord, since it is usually played as a V7 chord. Options added to allow a RealTrack to treat the V7 chord as a V (useful in rock styles), or to treat all 7th chords as major triads (useful in blues)."

The second half of the second sentence puzzles me, though, because it would seem to me that the opposite would be true; that is, it is useful in blues to treat major triads as dominants. But anyway . . .

Later.