Since the piano keyboard colors are fixed values of black and white, when the Selection Back color is black or white, the state of the keyscale display is obscured.
It would be useful to add a new color setting for the black and white keys on the piano keyboard (perhaps this is preferred) or a new color setting to replace the Selection Back in the key scale display.
It is not uncommon for various Themes to be incongruous only with respect to the color of the piano keyboard.
Considering the design consistency of the various Themes, it seems problematic to have fixed colors for the black and white keys.
I imagine that it is not always necessary to use a fixed color, since it is possible to distinguish which keys are black and which are white by their shape.
If you add a new black keyboard color (default color is black) and white keyboard color (default color is white) and only allow users to set other colors in newly created or modified themes, I assume it will not affect existing themes.
Please consider implementing this.