Only a pure delete was turned into a deletion mark; typing or pasting over
a selection ran as it was, so the replaced text left the document unmarked
and rejecting the change lost the original for good. A one-step replacement
now marks its range deleted and puts the new content after it, as both word
processors do.
With revision recording on, setContent inserted the whole file in one
transaction, so the recorder marked every run as the reader's own
insertion — the document then rendered underlined in the author colour
(#c69200) from the first character. Measured: 19 843 of 19 843 characters
on an 11-page import, 436 revision spans.
Both loads (new document, import) now carry the RECORDING meta; what is
typed after the open is still recorded, as in both word processors.