Change note entry to interpret white space clicks as scroll requests, not ledger note entry
Currently, clicking between staves during note entry inserts a note with many ledger lines. This is rarely intended; the user is instead probably trying to scroll the page. This violates the "Law of Least Astonishment." Such clicks should thus be treated as scroll requests, since there are other ways to enter notes with twelve ledger lines if desired. Optionally, draw the scrollable portions of the score canvas in a different color so that it is obvious where to click to move the display.