I have a suggestion for how the interface could be modified to make it easier to move the ribbon right or left relative to the display during performance.
Currently, you can move the ribbon by dragging the piano keyboard slider at the top of the screen when “keyboard and MIDI” is in focus. However, you cannot do this easily when you are actually playing a note because it is more or less impossible to control the pitch accurately while you are doing so.
My suggestion is to have a new button on the keyboard and midi panel. If you press this button with the finger of one hand while you are playing a note with a finger of the other hand, and then you slide that playing finger left or right, the finger will drag the ribbon left or right, rather than the finger moving left or right and leaving the ribbon where it is. This means that the finger will be able to keep the same pitch until the player releases the new button. Meanwhile, a new band of the ribbon will have become visible and playable on the display.
Obviously this will only work if only one finger is touching the ribbon, or if many fingers are touching the ribbon, but the player wants to move them all left or right at the same rate. Otherwise the movement of the ribbon relative to the display will be hard to predict and control.
Example:
You are playing a melody. You find yourself playing at the right-hand end of the display, and you want to play higher notes that are not yet accessible on the display. So you take advantage of a long sustained note to press and hold the new button while sliding the finger currently playing the note to the left. This will drag the ribbon to the left. Now those higher notes that you want to play will be accessible to you on the display.