Challenge 3: Deleting a Section Break Merges the Sections — Solution Walkthrough

What happens to Section 1's pages:

The moment the section break between Section 1 (portrait) and
Section 2 (landscape) is deleted, the two sections merge back into
one single section. The surviving, merged section adopts the
formatting of whichever section came AFTER the deleted break — in
this case, Section 2's landscape orientation. This means Section 1's
own pages, which were portrait a moment ago, immediately become
landscape too, even though nobody directly touched them or explicitly
asked for their orientation to change.

Why this happens:

A section break is the only thing marking where one section's
formatting definition ends and the next one's begins. Deleting that
marker doesn't average or reconcile the two sections' settings — it
simply removes the boundary between them, and Word needs to decide
which of the two formerly-separate formatting definitions now applies
to the whole newly-merged region. Word's behaviour here is to keep
the formatting that belonged to the section AFTER the break, which is
exactly why "cleaning up" a document by deleting a section break can
produce a surprising, seemingly unrelated formatting change to content
that was never directly edited at all.

Notes:
- This is precisely the scenario this chapter's own warning box
  describes — the colleague's "cleanup" wasn't a no-op the way
  deleting an ordinary page break would have been; it actively
  changed the appearance of pages nobody touched, because those pages
  depended entirely on the now-deleted break to keep their own
  formatting separate from their neighbour's.
- The safe way to remove a section break without this side effect is
  to first make sure both sections already share the SAME formatting
  before deleting the break between them — at that point, merging
  them changes nothing, since there's no longer any difference for
  the merge to expose.