OK, I've done some serious updates to my program, enough that I'm calling it version 1.0.

I've been working on this update for a couple months and I'm feeling really good about my latest progress.
Here's the latest screenshot:
Major updates include:
Generate scales, chords and modes for Major, Melodic minor and Harmonic minor scale types.
Generate scale based on chord starting note and chord type.
Playback scales as well as chords.
Ability to choose playback instrument.
I've tested this program in 10.3.9 and 10.4.0. It
should work in 10.2.8 aka Jaguar. If anyone here could confirm that would be most excellent.
Oh, before I forget, here's the link to the program page. The download link is at the bottom of the page.
http://dtibs.home.comcast.net
The source code for this program is included in the .dmg file in case anyone's interested in checking it out.
Are people still interested in this program? I'm debating whether to continue development and what direction to go next. I'm thinking about adding music sheet display of selected scales/chords next. Any ideas from you guys would be greatly appreciated.