Opening a second .docx used to mean a second browser tab: a whole ribbon,
banner and footer repeated, with one ✕ at the far end of a row that also
held the file's name. The name looked like a tab and nothing about it
behaved like one.
Now the editor holds documents the way the browser holds pages. A strip
under the toolbar carries one tab per open document — icon, name, unsaved
dot, its own ✕ — plus a + to open another. Middle-click closes, Ctrl+W
closes, Ctrl+Tab cycles, and right-click (or the caret on the tab under the
pointer) drops a menu: Duplicate, Open in the default app, Show in folder,
Close others, Close. The gestures are the browser's because that is the tab
strip every user of this editor already knows.
Under it, one ProseMirror view is handed a different state per document
rather than one view per tab, and the module-level "current document"
variables are marshalled in and out on a switch. That keeps the change out
of every function that touches the current document, at the price of one
list — DOC_FIELDS in captureActive/adoptDoc — that has to stay complete. A
variable missed there leaks one document's state into another, which would
look like the editor corrupting a file, so it is called out in a comment.
Closing the last document closes the editor tab, the way closing a
browser's last tab closes the window; an empty ribbon staring at the user
is not a state worth having.
The add-on hands a newly opened document to the editor that is already up
and fronts it, falling back to opening a tab if no editor acknowledges
within 900ms — so a crashed or closed editor degrades to exactly the old
behaviour rather than swallowing the document.
Moving it out of the build left it with no way in. Settings can only install
from the community catalogue, so a first-party extension that isn't bundled
has a working update channel and no first copy for anyone to update — the
mechanism was all there and the front door was missing.
So it goes back beside screenshot, aegis and pdf-editor: seeded into every
profile by the build, listed under "Built into Theseus", and kept current
between releases by the operator-signed channel at
theseus.x/extensions/docx-editor/. That is the arrangement docs/ADDON-UPDATES.md
describes, and the one the signing script was written for.
About 400 KB compressed in the installer, most of it the vendored editor
libraries — next to the ~4 MB of pdf.js that pdf-editor already ships, the
weight argument for keeping it out didn't survive contact with the numbers.
The end-to-end driver goes back to checking that a fresh profile seeds it,
which is the property that actually matters now.
A .docx editor is a megabyte of vendored library. Bundling it would charge
that to everyone who wanted a browser, including the people who will never
open a Word document in it.
So it leaves the build: out of bundled-addons/, out of extraResources, absent
from a fresh profile. It arrives the way anyone else's extension does —
Settings › Extensions › Community, from the catalogue the gateway builds, and
listed on theseus.x/extensions alongside everything else published there.
That also means it is signed by the owner of a BNS name rather than by the
operator key, which is the right trust story for something that isn't part of
the browser.
`npm run pack` produces the tarball the publish page takes; the signature
needs the publisher name's wallet, so it isn't something the repo can do.
The end-to-end test now installs the extension into a throwaway profile the
way the community installer would, and asserts up front that a fresh profile
doesn't already have it — the bundling is what was being removed, so it is
worth a test that would notice it coming back.
A .docx editor is easy to write badly: read the file into HTML, let someone
edit it, write a fresh document back, and hand them a file that lost its
headers, its page size and half its formatting without ever saying so.
Three things keep this one honest.
The reader doesn't use mammoth's HTML. mammoth's converter is deliberately
semantic, and HTML has nowhere to put a run's colour or a paragraph's line
spacing, so it drops them — and those are controls this editor puts in the
ribbon. Taking its parsed document model instead means what the ribbon offers
is what the file can actually carry. Six properties mammoth's model didn't
keep are added by build-time patches, each asserting its anchor so an upgrade
that moves the code fails the build rather than shipping a lossy reader.
The writer rebuilds the body but carries the rest of the package across:
headers, footers, footnotes, endnotes, the document's own style catalogue,
its theme and its page setup, with relationship ids and content types
re-wired. Word features the editor can't model are still lost, so they are
detected when the file opens and named in a banner before anyone edits.
Tracked changes get their own gate. mammoth renders insertions as ordinary
text and drops deletions, so saving would accept every pending revision
without Word ever asking. Such a document opens read-only until the user
says that is what they want.
Verified over 66 real documents: 65 round-trip with an identical model and a
structurally valid package, the one exception being a 7 MB WMF picture, which
no browser can display and the writer cannot emit. Also driven end to end
through a real Theseus over CDP — sidebar, ribbon, typing, save, reopen.
