Document::openRelativeFile: Double check the url changed when we asked to
If not, open did not succeed and the callers (for example open document X in page A) would like to know so they don't have to do the "change to part A" part.
If not, open did not succeed and the callers (for example open document X in page A) would like to know so they don't have to do the "change to part A" part.