up arrow - moves the selection up one slot
down arrow - moves the selection down one slot
left arrow - moves the selection left one voice
right arrow - moves the selection right one voice
home - moves to the top of the pattern
end - moves to the bottom of the pattern
page up - moves up in the pattern
page down - moves down in the pattern
return - moves the selection down one slot
delete - clears the selected slots
tab - toggles between the three text fields