// If this is e.g. a composite text box, it will need to be laid out itself.
// But if just a text fragment or image, for example, this will
// do nothing. NB: won't we need to set the position after layout?
// If this is e.g. a composite text box, it will need to be laid out itself.
// But if just a text fragment or image, for example, this will
// do nothing. NB: won't we need to set the position after layout?