Pressing the button drawn inside the page opens a dialog: a name, and a choice between one column and
two, then Create section. The row lands in the database and the frame re-renders to show it.
The layouts are DRAWN rather than named. "One column" is words for a shape, and a shape is faster to
recognise than to read; the words stay underneath for anybody the picture does not reach.
The name is asked for and not generated. It never appears on the site — it exists so a page of eight
bands is navigable, and "Section 4" tells nobody anything, which is exactly the state a generated name
would leave every page in. Asked at the only moment somebody knows what they are about to build.
The frame is remounted after a write rather than the admin drawing the new band itself. The site
renders from the database; the admin does not know how to render a page, and if it learnt it would be
a second implementation of the very thing this preview exists to avoid.
The canvas now finds the empty-page placeholder by its `data-page-empty` marker instead of taking
`firstElementChild`. That was right for exactly as long as an empty page was the only kind — the moment
a page has a section, the first child IS that section, and it would have hidden the thing being edited.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
A component that lives at the PLUGIN level and appears on the site's page: an empty drop zone with an
Add section button, injected into the frame at runtime. Nothing of it exists in the website's source,
so the site never carries code only an editor would see, and the builder can change without the site
being rebuilt.
It works because the preview frame is SAME ORIGIN — through the platform's dev proxy, on Officer's own
host — so contentDocument is readable and writable. That single fact is what the page builder rests on,
and it is why swapping this plugin's hand-rolled cross-origin proxy for the platform's mattered beyond
the bugs it fixed.
SitePreview grew one prop, `onDocument`, called with the frame's document after every load and
returning a cleanup that runs before the next one. So a reload never leaves two sets of controls
behind, and nothing injected outlives the document it went into.
Plain DOM rather than React. Portalling would mean running a reconciler against a document that reloads
underneath it whenever the dev server rebuilds; these are a handful of elements with a click handler,
and this way a reload is a document that no longer exists rather than a tree React still thinks it owns.
Inline styles, not classes. The frame carries the SITE's stylesheet, built by scanning the site's own
templates — a class invented in this file was never scanned and would silently do nothing. The button
takes its colours from --site-fg and --site-bg, so it belongs to whatever theme the site is wearing.
The page's existing content is HIDDEN rather than removed, so the same call will leave real blocks
visible once there are any.
The panel counts the presses for now. That is the only visible proof the wire runs both ways, and it
becomes the section picker when there are sections to pick.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>