Just in case anyone else has this issue . . . For my students, the color-coding of chord tones in the Melody and Chords - 2 Noteflight exercise was all wacky. The colors in the piano part did not match the chord tone colors above AND some of the notes were white. The reason was that my students (and I) were all using the Flash version of Noteflight. (It just came to us that way.) When I switched to the HTML5 version in the VIEW menu everything looked great. Plus, the piano keyboard is back.
Now I'm wondering, is there a way I can switch all of the students' views to HTML5 in one easy step. Probably not.