## Why
Full-page record tabs (Timeline, Tasks, Notes, Files, Emails, Calendar,
Flow) were encoded by storing a `CANVAS` layout mode. That made them a
separate species: editing one didn't feel native (no drag handles, no
way to add a second widget, the tab couldn't adapt), and the widget
pipeline was full of `layoutMode === CANVAS` branches.
This PR replaces the stored mode with two derived rules and one unified
header grammar:
> **Presentation is derived from content, never stored.**
> A list tab with exactly **one widget** renders it **solo**
(full-bleed, it owns the tab). Anything else is a **stack** of boxed
cards. **Edit mode always shows the stack structure.**
No widget taxonomy, no per-type branches: any lone widget owns its tab.
## What
**Presentation model**
- `getTabPresentation({ widgets, layoutMode, isInEditMode })`: solo iff
a list tab has exactly one widget in view mode; grid tabs (dashboards)
and edit mode are always stacks. The pinned left panel is always a
column (a surface rule, not a widget rule).
- Solo view rendering is identical to the old CANVAS rendering
(container height, internal scroll).
- Stacked widgets in the main tab area get one bounded slot rule
(`max-height` + own scroll) so no widget swallows the tab;
pinned/side-column stacks keep their flowing behavior. This only binds
on user-composed mixed tabs, which could not exist before.
**Native editing (the point of the PR)**
- Every record-page tab is edited through the same vertical-list editor:
drag handle, reorder, remove, add widget. Add a second widget to a
Timeline tab and it becomes a stack; remove back down to one and it's
solo again. Nothing is stored, nothing to migrate.
- Fixes the stuck-drag bug found while testing the preview: widgets
publishing header info republished a fresh object on every render
(activity cards build their action from non-memoized hook returns), and
since the widget chrome reads that state above the widget content, any
tab with an activity card sat in an infinite render loop. The loop
starved React's transition lane, which dnd-kit's drop teardown waits on,
so the drag clone and drop outlines froze on screen after a drop. The
header hook now republishes only on real value changes and routes
onClick through a stable wrapper, so callers need no memoization. The
page-layout drag provider also disables the Feedback drop animation so
clone cleanup is synchronous at drop time.
**Unified widget header API**
- A widget's content can publish header info to its chrome via
`usePublishWidgetHeaderInfo({ count, primaryAction })`: a count rendered
in grey next to the title, and a primary action (icon button with
accessible name) on the right in view mode. Instance-scoped state keyed
by widget id, so third-party widgets (front components) can use the same
seam later; the hook no-ops outside a page layout (stories, previews)
and is safe to call with inline, non-memoized values.
- A solo widget's header only appears when the widget published
something: the tab label already names it, so a bare title row adds
nothing. Timeline/Flow tabs stay exactly as today.
- Emails, Tasks, Notes, Files, Calendar publish their count (query
totals, not loaded-page lengths) and action (Compose, New task, New
note, Add file) and stop rendering internal title rows ("Inbox 12", "All
5"): exactly one header per widget everywhere, same grammar.
`ComposeEmailButton`, `AddTaskButton` and the title/button plumbing in
`NoteList`/`AttachmentList`/`TaskList` are deleted.
**Object-aware tabs**
- The hardcoded `SYSTEM_OBJECT_TABS` title allowlist is gone. A tab
renders based on whether the target object supports its widgets: widgets
that read through a relation (Tasks, Notes, Files, Timeline) require the
relation field to exist and be active, while Emails and Calendar
aggregate through the messaging timeline, so a missing participants
relation is fine (Company) and a deactivated one is an explicit opt-out.
System objects on the shared default layout keep exactly Home +
Timeline, now by derivation instead of hardcoded titles.
**Data cleanup**
- Seeds (frontend defaults, server standard template, `twenty app`
scaffolder, docs) write `VERTICAL_LIST`;
`PageLayoutTabLayoutMode.CANVAS` is `@deprecated`, kept read-only for
layouts persisted before this change (they render correctly through the
derivation; no data migration, by design: an in-place flip can't pass
the widget-position/tab-layoutMode validator atomically, and it isn't
needed).
- Locale catalogs are intentionally untouched: the i18n pipeline
extracts and translates the new header labels on main; they fall back to
their English source until then.
## Deliberate view-mode changes (approved)
- A lone widget of any type now owns its tab full-bleed: lone Fields tab
(mobile/side panel), lone rich-text Note tab, lone chart, and the
message-thread page lose their card box.
- Activity tabs show the unified header (title, grey count, + action)
instead of their internal "Inbox 12"-style rows.
Everything else is pixel-parity, including solo scroll behavior and
dashboards.
## Test plan
- `nx typecheck twenty-front` / `twenty-server`: clean; oxlint/oxfmt on
the changeset: clean
- 239 suites / 1474 tests across page-layout, activities, side-panel
pass, including new tests for `getTabPresentation` (count-based,
edit-mode override) and `usePublishWidgetHeaderInfo` (publish, cleanup
on unmount, no-op outside a widget, referential stability across
re-renders with inline actions, latest-onClick wrapper)
- `getTabsRenderableForTargetObject` tests covering missing vs
deactivated relations, Emails/Calendar without a participants relation,
and non-relation widgets
- Stuck-drag repro verified fixed end to end against a local stack with
an instrumented dnd-kit: before the fix the affected tab committed ~65
renders/second at idle and drops never tore down; after it, idle commits
are flat and every drop cleans up
Félix Malfait
6cc7ed7570