It would be nice to be able to make the black keys white and vice versa, so that the natural notes are black and the sharps and flats are white. This color scheme is typical of harpsichord keyboards.
I can do it temporarily by turning on View > Color Scale and using Edit > Color Palette > Chromatic Scale to set all the notes to black and white instead of the default rainbow colors. However, editing the chromatic scale colors seems to automatically set Edit > Preferences > Note Highlight Color to "Chromatic Scale" (with the effect of making the note highlights invisible, when the colors chosen are black and white), so I have to change that after editing the palette if I want to keep note highlights; and my changes to the color palette don't seem to be saved when I exit and restart the program, so I have to do this all over on each run. Having a separate adjustment for "natural key color" (default white) and "sharp/flat key color" (default black), saved like other configuration settings, would be preferable and should be easy to implement.