This is a good suggestion.

There are many other signs that are missing.
I think about a trill, bows, Appoggiatura, Acciaccatura, Glissando.
I tested a version of Sibelius 7. There are many signs in a small tool-window, that you can use to edit the score notation. I would be glad, if that ability would be in BIAB.
So there could be a seperate Edit window for the whole score as well. This would be very useful for classical music.

Michael Frank