A dictionary's state starts afresh, with a black fill. Mask art is written
going on from the paint before the mask's dictionary, which the writer leaves
out when it doesn't change, so a mask rectangle with no colour of its own
came in black and hid the white letters it masks. Mask art now starts from
the paint (fill, stroke, line style, fill rule, overprint) before the
dictionaries it is in; lock, visibility and transparency still start afresh.