When focusing on a particular bar of music it would be useful to be able using a modifier key with the pencil tool to play the note at the mouse position without entering the note.
Moving over to the left of the screen to click on the piano keyboard can break focus.
A key combination to scroll the screen one bar left (or right) would avoid having to take your eyes off a bar to find the scroll arrow.
This may seem like nit picking but anything which helps maintain focus is appreciated. Sometime the muse is easily distracted.