Based on the current chord symbol, display a helper window displaying the chord in root position, with an indication of which notes of the chord - and how many - are present in the score for the current horizontal timeslice.

For example, for a "CMaj7", display the chord graphically in a helper window such as:

B [7th]: In Bassoon and Flute
G [5th]: No notes
E [3rd ]: In Clarinet
C [root] : In Trumpet

Indicating which chordals are in use, and in what instrument(s).

Also, change the color of the note about to be entered if the note is chordal.