Ottavas should not have above/below staff placement property
c5f46bb. Enter some notes, and add an 8va or 8vb from the Lines palette.
In the Inspector, under Ottava, there is a Placement property that can be set to Above or Below. Switching this makes an 8va look like an 8vb and vice versa, though still transposing in the original direction. This property should not be available for ottavas.