why is anchorNode set to frameRoot as default and not just e.g. undefined, same with focusNode? they will be overwritten next anway. Currently the defaults are just confusing. I would propose to store the anchor container/offset in some dedicated helper vars anchorNode/anchorOffset instead, then set newSelection only by
```
newSelection = odtDocument.convertDomToCursorRange({
    anchorNode: anchorNode,
    anchorOffset: anchorOffset,
    focusNode: stepIterator.container(),
    focusOffset: stepIterator.offset()
});
```
Would be quicker to grasp on reading for me.