Stave space size awkward to edit
The stave space size in Page Settings is awkward to edit. As soon as one deletes a digit it is replaced with a zero. To see the effect put the cursor at the right-hand end of the number then press backspace. The entire field cannot be replaced if highlighted and a new value typed. The only way seems to be to inset the cursor at the right-hand end, backspace to convert the least significant digits to zeros, insert again at the right-hand end, backspace to remove the zeros, then type the required value. That's a very awkward manoeuvre.
Same comments apply to delete, unless then entire value of the stave space is highlighted.