Every plugin iframe loaded /plugin-sandbox, a force-dynamic Next page.
Each frame then fetched, parsed and hydrated Next's client router on top
of React and the runtime, and the server rendered the page once per
frame, one after another when a dozen plugins started together.
Sandboxed frames have opaque origins, so the browser's code cache never
helps, and they run on the host page's main thread: with 12 plugins
the frames took 2.5-3 s to come up after the app had loaded.
The sandbox routes now return a small HTML page with the UI kit's
stylesheet and the runtime as an ES module, both built ahead of time:
- `scripts/build-plugin-sandbox.mjs` bundles the runtime with esbuild
and compiles `plugin-kit.css` with the app's Tailwind setup into
`public/plugin-sandbox-assets/`, with a manifest. Named Tabler imports
are pointed at the icons' own files, so the full icon set stays in a
chunk that only loads for an icon name the kit doesn't ship.
- `npm run build`, `npm run dev`, the Dockerfile and the perf-guard
workflow run it before `next build`.
- `lib/plugin-sandbox/sandbox-document.ts` writes the page; proxy.ts
still sets the sandbox CSP and the script carries its nonce.
- The assets are served from public/ with CORS and immutable caching.
A frame on an idle page is ready in 255 ms instead of 362 ms, eleven at
once in 1.0 s instead of 2.1 s.
Plugins running in iframe sandboxes previously lacked access to the user's regional formatting settings (dateLocale, timeFormat 12h/24h, timeZone, and firstDayOfWeek) unless they requested privileged settings:read permissions.
This mirrors the host's resolved presentation preferences into the plugin sandbox:
- Adds RegionalSnapshot (locale, dateLocale, hour12, timeZone, firstDayOfWeek) to BackgroundInit, SlotInit, and LocaleChangeMsg.
- Implements snapshotRegionalSettings() in host-bridge, reusing host resolveDateLocale() and getEffectiveTimeZone().
- Subscribes stores/plugin-store.ts to useSettingsStore to broadcast updates to running sandboxes when regional preferences change.
- Exposes api.i18n.formatTime(date, options) and api.i18n.formatDate(date, options) along with regional getters on api.i18n.
A new feature gate, tagsAboveSharedEnabled (default off, so the sidebar
keeps its order), lists the Tags section above the shared mailboxes
instead of below them. With many shared mailboxes expanded, the tags
otherwise end up out of sight. In Mountain View the tags then follow the
Labels list directly, also when More is open.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Linus Rath
Linus Rath
Tobias Genannt
Jacob ZeitzandClaude Opus 5.5