@@ -0,0 +1,19 @@
+---
+'@object-ui/app-shell': patch
+'@object-ui/components': patch
+'@object-ui/plugin-detail': patch
+'@object-ui/i18n': patch
+---
+
+feat(app-shell,plugin-detail,components,i18n): the record page's timeline and related columns are each reader's switches, per object, toggled from the crumb row
+
+Clause-②: no
+Metadata-protocol: none
+
+Whether the record page shows its timeline column and its related column is now the reader's own choice, per object, kept in the browser. It is not metadata: no key, no spec change.
+
+- **Defaults derived from the object.** A reader who never chose gets the timeline on for a "worked" object and off otherwise, and the related column on. An object is worked when `stageField` names a field, when a field's options declare a lifecycle `kind` (unless `stageField: false`), or when it sets `enable.files: true` — only what the object declares of itself. Being another object's `master_detail` parent does not count: a container that owns child rows (a price book, a campaign) is not a worked record. `recordTimelineDefaultReason` and `recordPageColumnDefaults` in `@object-ui/plugin-detail` say which.
+- **A switched-off column frees its room.** With the timeline off, a wide page draws details | related, and the timeline's blocks (the composer and History) become an Activity card at the foot of the related column. With the related column off, it stays behind the rail toggle. `recordPageArrangementFor` is the rule, and `RecordPageColumns` takes the reader's `switches`. Below the column widths the page is tabbed as before, the switches are kept for when it widens, and `?tab=` is unchanged.
+- **Panel toggles.** `PanelToggles` in `@object-ui/components` is a group of icon toggles with `aria-pressed`, a tinted pressed state, and a tooltip naming the shortcut. The record page draws it on its crumb row, right side, only in a column tier. It is not drawn in the drawer or split pane.
+- **Shortcuts.** `⌘⇧.` / `Ctrl+Shift+.` toggles the timeline and `⌘⇧,` / `Ctrl+Shift+,` the related column, matched by the physical key. Not `⌘⇧T` / `⌘⇧R`: the browser keeps those (reopen closed tab, hard reload) and the page never receives them. They do nothing while a text field has focus, and the keyboard-shortcuts dialog lists them while the record page is open.
+- **One preference store.** `app-shell`'s `workspacePreference` module keeps every reader preference by preference and scope (`user`, or `object:OBJECT_NAME`). Each value is a small record with a version `v`. It reads live through `useSyncExternalStore`, follows other tabs, and falls back to the default with no storage. The record-open preference (`os:record-open-mode`) is now a thin alias over it and keeps its stored spelling, so a reader's earlier choice reads back unchanged.
@@ -6,7 +6,13 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import { useCallback, useSyncExternalStore } from 'react';
+import {
+  defineWorkspacePreference,
+  readWorkspacePreference,
+  useWorkspacePreference,
+  writeWorkspacePreference,
+  workspacePreferenceStorage,
+} from './workspacePreference.js';
 
 /**
  * How the console's object page opens a record a reader clicks, when the
@@ -34,6 +40,13 @@ import { useCallback, useSyncExternalStore } from 'react';
  * It never overrides a declaration: an object whose resolved mode is `page`,
  * `new_window` or `none` ignores it, because the host reads it only for a
  * drawer-mode record.
+ *
+ * A thin alias over the console's one preference store,
+ * `workspacePreference.ts` (objectstack#27052): the preference is
+ * {@link RECORD_OPEN_PREFERENCE} there, in the `user` scope, and it keeps the
+ * spelling it was first stored with — a bare `drawer` / `split` under
+ * {@link RECORD_OPEN_PREFERENCE_KEY} — so a reader's earlier choice reads
+ * back unchanged.
  */
 export type RecordOpenPreference = 'drawer' | 'split';
 
@@ -49,15 +62,19 @@ export type RecordOpenPreferenceStorage = Pick<Storage, 'getItem'>;
 /** The storage surface this module writes — `localStorage`, or a test double. */
 export type RecordOpenPreferenceWriteStorage = Pick<Storage, 'setItem'>;
 
-function defaultStorage(): Storage | null {
-  if (typeof window === 'undefined') return null;
-  try {
-    return window.localStorage;
-  } catch {
-    // Accessing `localStorage` itself throws on a blocked origin.
-    return null;
-  }
-}
+/**
+ * The preference in the console's store: one key for every object (`user`
+ * scope), stored as the bare value. Any other stored spelling — an unknown
+ * value, a retired mode name, another case — is no choice.
+ */
+export const RECORD_OPEN_PREFERENCE = defineWorkspacePreference<RecordOpenPreference>({
+  name: 'record.open-mode',
+  storageKey: () => RECORD_OPEN_PREFERENCE_KEY,
+  codec: {
+    decode: (stored) => (stored === 'split' || stored === 'drawer' ? stored : undefined),
+    encode: (value) => value,
+  },
+});
 
 /**
  * The reader's record-open preference, or {@link DEFAULT_RECORD_OPEN_PREFERENCE}
@@ -66,30 +83,11 @@ function defaultStorage(): Storage | null {
  * says there is none.
  */
 export function readRecordOpenPreference(
-  storage: RecordOpenPreferenceStorage | null = defaultStorage(),
+  storage: RecordOpenPreferenceStorage | null = workspacePreferenceStorage(),
 ): RecordOpenPreference {
-  if (!storage) return DEFAULT_RECORD_OPEN_PREFERENCE;
-  try {
-    const stored = storage.getItem(RECORD_OPEN_PREFERENCE_KEY);
-    return stored === 'split' || stored === 'drawer' ? stored : DEFAULT_RECORD_OPEN_PREFERENCE;
-  } catch {
-    return DEFAULT_RECORD_OPEN_PREFERENCE;
-  }
+  return readWorkspacePreference(RECORD_OPEN_PREFERENCE, 'user', storage) ?? DEFAULT_RECORD_OPEN_PREFERENCE;
 }
 
-/**
- * A choice storage would not keep, held for this page: a browser whose
- * storage refuses the write (private mode, a full quota, a blocked origin)
- * would otherwise have the reader pick 分屏 and keep reading 抽屉 back.
- * `undefined` while storage keeps the choice — storage is then the one answer
- * — and cleared by the next kept write and by another tab's write (see
- * `subscribe`).
- */
-let pageChoice: RecordOpenPreference | undefined;
-
-/** The live {@link useRecordOpenPreference} callers on this page. */
-const listeners = new Set<() => void>();
-
 /**
  * Keep the reader's choice. `storage` defaults to the browser's
  * `localStorage`; `null` says there is none. With no storage, or one that
@@ -103,42 +101,9 @@ const listeners = new Set<() => void>();
  */
 export function writeRecordOpenPreference(
   next: RecordOpenPreference,
-  storage: RecordOpenPreferenceWriteStorage | null = defaultStorage(),
+  storage: RecordOpenPreferenceWriteStorage | null = workspacePreferenceStorage(),
 ): void {
-  pageChoice = next;
-  if (storage) {
-    try {
-      storage.setItem(RECORD_OPEN_PREFERENCE_KEY, next);
-      pageChoice = undefined;
-    } catch {
-      // Not kept past this page — see above.
-    }
-  }
-  for (const listener of Array.from(listeners)) listener();
-}
-
-function subscribe(onChange: () => void): () => void {
-  listeners.add(onChange);
-  const onStorage = (event: StorageEvent) => {
-    // `key === null` is a `clear()` in another tab.
-    if (event.key === RECORD_OPEN_PREFERENCE_KEY || event.key === null) {
-      pageChoice = undefined;
-      onChange();
-    }
-  };
-  if (typeof window !== 'undefined') window.addEventListener('storage', onStorage);
-  return () => {
-    listeners.delete(onChange);
-    if (typeof window !== 'undefined') window.removeEventListener('storage', onStorage);
-  };
-}
-
-function snapshot(): RecordOpenPreference {
-  return pageChoice ?? readRecordOpenPreference();
-}
-
-function serverSnapshot(): RecordOpenPreference {
-  return DEFAULT_RECORD_OPEN_PREFERENCE;
+  writeWorkspacePreference(RECORD_OPEN_PREFERENCE, 'user', next, storage);
 }
 
 /**
@@ -148,7 +113,5 @@ function serverSnapshot(): RecordOpenPreference {
  * object page decides its split face from the value the reader just chose.
  */
 export function useRecordOpenPreference(): [RecordOpenPreference, (next: RecordOpenPreference) => void] {
-  const preference = useSyncExternalStore(subscribe, snapshot, serverSnapshot);
-  const setPreference = useCallback((next: RecordOpenPreference) => writeRecordOpenPreference(next), []);
-  return [preference, setPreference];
+  return useWorkspacePreference(RECORD_OPEN_PREFERENCE, 'user', DEFAULT_RECORD_OPEN_PREFERENCE);
 }
@@ -0,0 +1,106 @@
+/**
+ * ObjectUI
+ * Copyright (c) 2024-present ObjectStack Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * objectstack#27052 — `useWorkspacePreference`, the live read: the fallback
+ * while there is no choice, every caller of the same preference and scope
+ * re-rendered by a write, a scope apart from every other, another tab's write
+ * heard through the `storage` event, and a choice a refusing storage would
+ * not keep held for this page.
+ */
+
+import * as React from 'react';
+import { describe, it, expect, afterEach, vi } from 'vitest';
+import { render, screen, cleanup, act, fireEvent } from '@testing-library/react';
+import {
+  RECORD_TIMELINE_COLUMN_PREFERENCE,
+  objectPreferenceScope,
+  useWorkspacePreference,
+  workspacePreferenceStorageKey,
+  type PreferenceSwitch,
+  type WorkspacePreferenceScope,
+} from './workspacePreference';
+
+const LEAD = objectPreferenceScope('crm_lead');
+const PRODUCT = objectPreferenceScope('crm_product');
+const LEAD_KEY = workspacePreferenceStorageKey(RECORD_TIMELINE_COLUMN_PREFERENCE, LEAD);
+
+function Probe({ id, scope, fallback }: { id: string; scope: WorkspacePreferenceScope; fallback: PreferenceSwitch }) {
+  const [value, setValue] = useWorkspacePreference(RECORD_TIMELINE_COLUMN_PREFERENCE, scope, fallback);
+  return (
+    <button type="button" data-testid={id} onClick={() => setValue(value === 'on' ? 'off' : 'on')}>
+      {value}
+    </button>
+  );
+}
+
+afterEach(() => {
+  cleanup();
+  vi.restoreAllMocks();
+  window.localStorage.clear();
+});
+
+describe('useWorkspacePreference (objectstack#27052)', () => {
+  it('answers the fallback with no choice; a write re-renders every caller of the same scope, and no other', () => {
+    render(
+      <>
+        <Probe id="a" scope={LEAD} fallback="on" />
+        <Probe id="b" scope={LEAD} fallback="on" />
+        <Probe id="product" scope={PRODUCT} fallback="off" />
+      </>,
+    );
+    expect(screen.getByTestId('a').textContent).toBe('on');
+    expect(screen.getByTestId('product').textContent).toBe('off');
+    fireEvent.click(screen.getByTestId('a'));
+    expect(screen.getByTestId('a').textContent).toBe('off');
+    expect(screen.getByTestId('b').textContent).toBe('off');
+    expect(screen.getByTestId('product').textContent).toBe('off');
+    expect(JSON.parse(window.localStorage.getItem(LEAD_KEY)!)).toEqual({ value: 'off', v: 1 });
+  });
+
+  it('the choice survives a remount (a reload reads the same storage)', () => {
+    const first = render(<Probe id="a" scope={LEAD} fallback="on" />);
+    fireEvent.click(screen.getByTestId('a'));
+    first.unmount();
+    render(<Probe id="a" scope={LEAD} fallback="on" />);
+    expect(screen.getByTestId('a').textContent).toBe('off');
+  });
+
+  it("hears another tab's write through the `storage` event", () => {
+    render(<Probe id="a" scope={LEAD} fallback="on" />);
+    act(() => {
+      window.localStorage.setItem(LEAD_KEY, JSON.stringify({ value: 'off', v: 1 }));
+      window.dispatchEvent(new StorageEvent('storage', { key: LEAD_KEY }));
+    });
+    expect(screen.getByTestId('a').textContent).toBe('off');
+    act(() => {
+      window.localStorage.clear();
+      window.dispatchEvent(new StorageEvent('storage', { key: null }));
+    });
+    expect(screen.getByTestId('a').textContent).toBe('on');
+  });
+
+  it('holds a choice a refusing storage would not keep, for this page', () => {
+    const real = window.localStorage;
+    const refusing = {
+      getItem: (key: string) => real.getItem(key),
+      setItem: () => {
+        throw new Error('QuotaExceededError');
+      },
+    };
+    Object.defineProperty(window, 'localStorage', { value: refusing, configurable: true });
+    try {
+      render(<Probe id="a" scope={LEAD} fallback="on" />);
+      fireEvent.click(screen.getByTestId('a'));
+      expect(screen.getByTestId('a').textContent).toBe('off');
+      expect(real.getItem(LEAD_KEY)).toBeNull();
+    } finally {
+      Object.defineProperty(window, 'localStorage', { value: real, configurable: true });
+    }
+  });
+});
@@ -0,0 +1,118 @@
+/**
+ * ObjectUI
+ * Copyright (c) 2024-present ObjectStack Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * objectstack#27052 — the console's one workspace-preference store: a
+ * preference × scope keyed `localStorage` entry holding a small versioned
+ * record, read as "no choice" whenever it cannot be read. This file runs in
+ * the node project (no `window`); the live hook and its cross-tab path are
+ * driven in `workspacePreference.hook.test.tsx`.
+ */
+
+import { describe, it, expect } from 'vitest';
+import {
+  RECORD_RELATED_COLUMN_PREFERENCE,
+  RECORD_TIMELINE_COLUMN_PREFERENCE,
+  defineWorkspacePreference,
+  objectPreferenceScope,
+  readWorkspacePreference,
+  versionedPreferenceCodec,
+  workspacePreferenceStorageKey,
+  writeWorkspacePreference,
+} from './workspacePreference';
+
+const memoryStorage = () => {
+  const kept = new Map<string, string>();
+  return {
+    kept,
+    getItem: (key: string) => kept.get(key) ?? null,
+    setItem: (key: string, value: string) => void kept.set(key, value),
+  };
+};
+
+describe('workspacePreference keys (objectstack#27052)', () => {
+  it('one key per preference × scope; the per-object scope names the object', () => {
+    expect(objectPreferenceScope('crm_lead')).toBe('object:crm_lead');
+    expect(workspacePreferenceStorageKey(RECORD_TIMELINE_COLUMN_PREFERENCE, objectPreferenceScope('crm_lead'))).toBe(
+      'os:pref:record.columns.timeline@object:crm_lead',
+    );
+    expect(workspacePreferenceStorageKey(RECORD_RELATED_COLUMN_PREFERENCE, objectPreferenceScope('crm_lead'))).toBe(
+      'os:pref:record.columns.related@object:crm_lead',
+    );
+    const userScoped = defineWorkspacePreference({ name: 'demo.user', codec: { decode: (s) => s, encode: (v: string) => v } });
+    expect(workspacePreferenceStorageKey(userScoped)).toBe('os:pref:demo.user');
+  });
+
+  it('a preference with a spelling of its own keeps it', () => {
+    const legacy = defineWorkspacePreference({
+      name: 'demo.legacy',
+      storageKey: () => 'os:demo-legacy',
+      codec: { decode: (s) => s, encode: (v: string) => v },
+    });
+    const storage = memoryStorage();
+    writeWorkspacePreference(legacy, 'user', 'kept', storage);
+    expect(storage.kept.get('os:demo-legacy')).toBe('kept');
+  });
+});
+
+describe('the column switches — a versioned record (objectstack#27052)', () => {
+  const lead = objectPreferenceScope('crm_lead');
+  const product = objectPreferenceScope('crm_product');
+
+  it('stores a record carrying `v`, and reads it back per object', () => {
+    const storage = memoryStorage();
+    writeWorkspacePreference(RECORD_TIMELINE_COLUMN_PREFERENCE, lead, 'off', storage);
+    const stored = JSON.parse(storage.kept.get('os:pref:record.columns.timeline@object:crm_lead')!);
+    expect(stored).toEqual({ value: 'off', v: 1 });
+    expect(readWorkspacePreference(RECORD_TIMELINE_COLUMN_PREFERENCE, lead, storage)).toBe('off');
+    // Another object, and the other column, have no choice.
+    expect(readWorkspacePreference(RECORD_TIMELINE_COLUMN_PREFERENCE, product, storage)).toBeUndefined();
+    expect(readWorkspacePreference(RECORD_RELATED_COLUMN_PREFERENCE, lead, storage)).toBeUndefined();
+    writeWorkspacePreference(RECORD_TIMELINE_COLUMN_PREFERENCE, lead, 'on', storage);
+    expect(readWorkspacePreference(RECORD_TIMELINE_COLUMN_PREFERENCE, lead, storage)).toBe('on');
+  });
+
+  it('reads no choice from a record of another version, a value it does not know, or a spelling that is not a record', () => {
+    const key = 'os:pref:record.columns.timeline@object:crm_lead';
+    const storageWith = (value: string) => ({ getItem: (k: string) => (k === key ? value : null) });
+    for (const spelling of ['{"value":"off","v":2}', '{"value":"off"}', '{"value":"hidden","v":1}', 'off', '[1]', 'null', '{']) {
+      expect(readWorkspacePreference(RECORD_TIMELINE_COLUMN_PREFERENCE, lead, storageWith(spelling))).toBeUndefined();
+    }
+  });
+
+  it('reads no choice with no storage, or with one that throws; a write to either throws nothing', () => {
+    expect(readWorkspacePreference(RECORD_TIMELINE_COLUMN_PREFERENCE, lead, null)).toBeUndefined();
+    const throwing = { getItem: () => { throw new Error('SecurityError'); } };
+    expect(readWorkspacePreference(RECORD_TIMELINE_COLUMN_PREFERENCE, lead, throwing)).toBeUndefined();
+    expect(() => writeWorkspacePreference(RECORD_TIMELINE_COLUMN_PREFERENCE, lead, 'off', null)).not.toThrow();
+    const refusing = { setItem: () => { throw new Error('QuotaExceededError'); } };
+    expect(() => writeWorkspacePreference(RECORD_TIMELINE_COLUMN_PREFERENCE, product, 'off', refusing)).not.toThrow();
+  });
+
+  it('with no `window` (SSR — this file runs in the node project), the default storage is absent: no choice', () => {
+    expect(typeof window).toBe('undefined');
+    expect(readWorkspacePreference(RECORD_RELATED_COLUMN_PREFERENCE, lead)).toBeUndefined();
+  });
+});
+
+describe('versionedPreferenceCodec (objectstack#27052)', () => {
+  it('a record-shaped value round-trips; `v` is written last and always', () => {
+    const codec = versionedPreferenceCodec<{ order: string[]; collapsed: string[] }>({
+      version: 3,
+      toRecord: (value) => ({ ...value }),
+      fromRecord: (record) =>
+        Array.isArray(record.order) && Array.isArray(record.collapsed)
+          ? { order: record.order as string[], collapsed: record.collapsed as string[] }
+          : undefined,
+    });
+    const spelling = codec.encode({ order: ['a', 'b'], collapsed: ['b'] });
+    expect(JSON.parse(spelling)).toEqual({ order: ['a', 'b'], collapsed: ['b'], v: 3 });
+    expect(codec.decode(spelling)).toEqual({ order: ['a', 'b'], collapsed: ['b'] });
+    expect(codec.decode('{"order":[],"collapsed":[],"v":2}')).toBeUndefined();
+  });
+});