It dawned on me yesterday that ChordEase needs a virtual piano interface that you can play via the mouse and/or the PC keyboard. This would allow people who haven't got a MIDI instrument to try out ChordEase, using the Microsoft software synth that's built in to Windows. This feature would also be very handy for debugging in cafes. :) And, it should be possible for the virtual piano's keys to show which notes they're mapped to at any given moment, which would allow you to see how the chord scale is changing as you proceed through the song.
The virtual piano would need a drop list for selecting which part you want to play. It would be nice if it also had a slider or two, for testing controllers that you've assigned to parameters. It's not that much work and it's high value, compared to many other items on the list, though documentation is still the top priority. The list is growing exponentially at the moment, but that's normal at this stage of a project.