"Even if there were an event you could trap, I hardly imagine you'd want to wait for perhaps a Minute"

correct, only this part
If strRef <> strStl Then .Code.Text = Replace(.Code.Text, strRef, strStl)
seems to be uncritical as Long as you operate an assessable range and perform field updates later.

In fact, in most cases only some paragraphs are concerned and Need to be updated

Example. The user will change the Headline 1.2 to 1.1.3. The update range will be the red area. Only REFSTYLE fields in those paragraphs must be detected and changed. If the user has finished all changes he can click on an update button, to check the results.

1.1 Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor

invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata

1.2 sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr
- justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata
- justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata

At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren,
At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren,
At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren

2 sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren,

no sea takimata sanctus est Lorem ipsum dolor sit amet