@@ -0,0 +1,27 @@
+---
+'@object-ui/types': minor
+'@object-ui/plugin-grid': minor
+---
+
+feat(types)!: retire `object-grid`'s `resizableColumns` on both faces, and stop `ObjectGrid` reading it (objectui#6152, round 7)
+
+**Retired (breaking).** `resizableColumns` was the legacy second spelling of `resizable` on
+`object-grid`, read only when `resizable` was absent. `@objectstack/spec` 17.7.0 retired it in the
+`object-grid` row (objectstack#21445), so an authored document that writes it, flat on the node or
+inside its `properties` bag, was already refused by name before this change. This change retires
+the rest of it, with no alias window:
+
+- `@object-ui/types`: `ObjectGridSchema.resizableColumns` is now `?: never`, so writing it on a
+  typed literal is a `tsc` error. The flat zod `ObjectGridSchema` in `@object-ui/types/zod` (the
+  node as `ObjectGrid` reads it after the `properties` hoist, or as code composes it) refuses the
+  key by name at the key, where `.passthrough()` used to keep it unexamined. The refusal names
+  `properties.resizable`.
+- `@object-ui/plugin-grid`: `ObjectGrid` reads `resizable` alone. A node that still carries
+  `resizableColumns` (one composed in code, past the type) now gets the default, resizable
+  columns, as if it had written nothing: `resizableColumns: false` no longer turns the column
+  resize handles off. The `object-grid` registration's `resizable` input no longer describes the
+  old spelling as a fallback.
+
+Rename the key to `resizable`; on an authored node, that is `properties.resizable`.
+
+An `object-view`'s `table.resizableColumns` is unchanged: the slot already refused it by name.
@@ -5431,7 +5431,11 @@ export const ObjectGrid: React.FC<ObjectGridComponentProps> = ({
     // `editable` produces no such column today. Following the same verdict is
     // what makes the gated grid identical to the non-editable one.
     rowActions: !!(inlineEditable && hasActions),
-    resizableColumns: schema.resizable ?? schema.resizableColumns ?? true,
+    // `resizable` alone (objectui#6152 round 7): the legacy `resizableColumns`
+    // spelling is retired on both faces and by `@objectstack/spec` 17.7.0, so
+    // it is no longer read here. (`resizableColumns` on the left is DataTable's
+    // own prop, a different block's key.)
+    resizableColumns: schema.resizable ?? true,
     reorderableColumns: schema.reorderableColumns ?? false,
     // [#5143] The authored key ∧ this principal's write verdict on the object.
     editable: inlineEditable,
 
@@ -0,0 +1,80 @@
+/**
+ * objectui#6152 round 7 — `ObjectGrid` reads `resizable` alone.
+ *
+ * `resizableColumns` was the legacy second spelling of `resizable`, read only when
+ * `resizable` was absent (`schema.resizable ?? schema.resizableColumns ?? true`). It is
+ * retired on both faces of `@object-ui/types` and by `@objectstack/spec` 17.7.0, which
+ * refuses it in the `object-grid` row, so the fallback read went in the same change:
+ * a node that still carries the old spelling (one composed in code, past the type)
+ * gets the default, resizable columns, exactly as if it had written nothing.
+ *
+ * Observed in the DOM: each resizable header cell draws one `.cursor-col-resize` drag
+ * handle (`data-table`'s own markup, the one `columnStatePersistence.test.tsx` drags).
+ */
+import { describe, it, expect, beforeEach } from 'vitest';
+import { render, screen, waitFor } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import React from 'react';
+import type { ObjectGridSchema } from '@object-ui/types';
+
+import { ObjectGrid } from '../ObjectGrid';
+import { __clearRecordCrudVerdictCache } from '../hooks/useRecordCrudVerdicts';
+import { installExplainDouble } from './explainDouble';
+import { registerAllFields } from '@object-ui/fields';
+import { ActionProvider } from '@object-ui/react';
+
+registerAllFields();
+
+beforeEach(() => {
+  __clearRecordCrudVerdictCache();
+  installExplainDouble();
+  localStorage.clear();
+});
+
+const rows = [
+  { id: '1', name: 'Alice', amount: 100 },
+  { id: '2', name: 'Bob', amount: 200 },
+];
+
+/** Render a two-column grid and count the header resize handles it draws. */
+async function resizeHandles(extra: Record<string, unknown>): Promise<number> {
+  // Cast through `unknown`: the retired spelling is a `tsc` error on `ObjectGridSchema`
+  // now, and this writes it on purpose, as a node composed past the type would.
+  const schema = {
+    type: 'object-grid',
+    objectName: 'test_object',
+    columns: [
+      { field: 'name', label: 'Name' },
+      { field: 'amount', label: 'Amount', type: 'number' },
+    ],
+    data: { provider: 'value', items: rows },
+    ...extra,
+  } as unknown as ObjectGridSchema;
+  const { container, unmount } = render(
+    <ActionProvider>
+      <ObjectGrid schema={schema} />
+    </ActionProvider>,
+  );
+  await waitFor(() => expect(screen.getByText('Alice')).toBeInTheDocument());
+  const count = container.querySelectorAll('th .cursor-col-resize').length;
+  unmount();
+  return count;
+}
+
+describe('objectui#6152 round 7 — `ObjectGrid` no longer reads `resizableColumns`', () => {
+  it('CONTROL: with neither key, both columns draw a resize handle (on by default)', async () => {
+    expect(await resizeHandles({})).toBe(2);
+  });
+
+  it('LIT CONTROL: `resizable: false` turns the handles off, so the count can move', async () => {
+    expect(await resizeHandles({ resizable: false })).toBe(0);
+  });
+
+  it('`resizableColumns: false` alone is not read: the grid keeps its default handles', async () => {
+    expect(await resizeHandles({ resizableColumns: false })).toBe(2);
+  });
+
+  it('`resizable: false` still wins when the retired spelling says otherwise', async () => {
+    expect(await resizeHandles({ resizable: false, resizableColumns: true })).toBe(0);
+  });
+});
@@ -211,6 +211,9 @@ export const ObjectGridRenderer: React.FC<{ schema: any; [key: string]: any }> =
  * turned it into a retired-key tombstone the protocol refuses by name, and
  * objectui#5861 removed every renderer read of it (ADR-0049 enforce-or-remove).
  * It stays off this list because the contract refuses it, not by exemption.
+ * `resizableColumns` followed the same way: spec 17.7.0 tombstoned it
+ * (objectstack#21445), and objectui#6152 round 7 removed `ObjectGrid`'s
+ * `resizable ?? resizableColumns` read, so `resizable` is its only spelling.
  *
  * ## `description`, `emptyState` and `keyboardNavigation`: the 17.6.0 keys
  *
@@ -298,7 +301,7 @@ const GRID_QUERY_INPUTS: ComponentInput[] = [
   // ── presentation ──────────────────────────────────────────────────────────
   { name: 'rowHeight', type: 'enum', enum: ['compact', 'short', 'medium', 'tall', 'extra_tall'], description: 'Row density. An unrecognised value falls back to `compact` rather than erroring.' },
   { name: 'frozenColumns', type: 'number', description: 'How many leading columns stay pinned while the grid scrolls horizontally.' },
-  { name: 'resizable', type: 'boolean', description: 'Let users drag column borders to resize. The canonical spelling — the deprecated `resizableColumns` is only read when this is absent.' },
+  { name: 'resizable', type: 'boolean', description: 'Let users drag column borders to resize. On by default. The only spelling — the legacy `resizableColumns` is retired and refused by name (objectui#6152).' },
   { name: 'reorderableColumns', type: 'boolean', description: 'Let users drag columns into a different order.' },
   { name: 'showColumnTypeIcons', type: 'boolean', description: 'Show a field-type icon in each column header. Off by default — the type is usually obvious from the cell content, and the icons compete with the column labels.' },
   { name: 'rowColor', type: 'object', description: 'Rules that colour whole rows from a field value.' },
 
@@ -152,7 +152,12 @@ const TABLE_WITHHELD_BY_REASON = {
    * of these to it.
    */
   nodeLevel: ['ariaLabel', 'disabled', 'disabledOn', 'hidden', 'hiddenOn', 'responsiveStyles', 'style', 'testId', 'visible', 'visibleOn', 'visibleWhen'],
-  /** The legacy alias of a relayed key: `bulkActions`, `resizable`. */
+  /**
+   * The legacy alias of a relayed key: `bulkActions`, `resizable`. `resizableColumns`
+   * is also a retirement tombstone on `ObjectGridSchema` itself since objectui#6152
+   * round 7 (`ObjectGrid` no longer reads it); the slot still refuses it with its own
+   * message, as it does the `unread` five.
+   */
   alias: ['batchActions', 'resizableColumns'],
 } as const;
 
@@ -163,7 +168,8 @@ const TABLE_WITHHELD_KEYS: readonly string[] = Object.values(TABLE_WITHHELD_BY_R
  * faces) that the slot keeps: they type nothing, and they carry the named
  * refusal and its guidance onto this face too. The five the grid retired in
  * objectui#11068 are in the withheld set above instead, refused by the slot's
- * own message.
+ * own message, and so is `resizableColumns`, which the grid retired in
+ * objectui#6152 round 7.
  */
 const TABLE_INHERITED_TOMBSTONES = ['body', 'children', 'defaultSort'] as const;
 
 
@@ -23,8 +23,10 @@
  * The authored `object-grid` node does not move: its bag is the spec row by
  * reference, and a prop written flat on the node stays refused by name.
  *
- * `resizableColumns`, the eleventh key, is NOT mirrored. Its route is open on the
- * card, and `zod-mirror-parity.test.ts` keeps it in `UnmirroredDeclared`.
+ * `resizableColumns`, the eleventh key, was NOT mirrored: its route was open on the
+ * card until round 7 RETIRED it. It is a member of the mirror since then, as a
+ * retirement tombstone that refuses every value, and `zod-mirror-parity.test.ts`
+ * no longer ledgers it (`unmirrored-declared-round7-6152.test.ts` pins the rest).
  */
 import { describe, it, expect } from 'vitest';
 
@@ -92,8 +94,15 @@ describe('objectui#6152 round 6 — the flat `ObjectGridSchema` mirror judges te
     expect(refused.every((i) => i.path[0] === key), JSON.stringify(refused)).toBe(true);
   });
 
-  it('`resizableColumns` is NOT mirrored: its route is open, and the parity ledger keeps it', () => {
-    expect('resizableColumns' in ObjectGridSchema.shape).toBe(false);
+  it('`resizableColumns` was not mirrored but RETIRED (round 7): a member that refuses every value', () => {
+    // Flipped by objectui#6152 round 7. This read `false` while the key's route was
+    // open; the retirement made it a tombstone member, which is what a passthrough
+    // mirror needs to refuse the key instead of keeping it unexamined.
+    expect('resizableColumns' in ObjectGridSchema.shape).toBe(true);
+    for (const value of [true, false]) {
+      expect(codeAndPath(ObjectGridSchema.safeParse({ ...GRID, resizableColumns: value })))
+        .toEqual([{ code: 'invalid_type', path: ['resizableColumns'] }]);
+    }
   });
 
   it('the members the twin takes from the spec by name are the spec\'s, by reference', () => {
 
@@ -0,0 +1,132 @@
+/**
+ * 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.
+ *
+ * objectui#6152 round 7 — `ObjectGridSchema.resizableColumns` RETIRED on both faces.
+ *
+ * `resizable` is canonical, and `resizableColumns` (its legacy second spelling, read only
+ * when `resizable` was absent) retires with no window. Round 6 stopped at the key: the
+ * authored `object-grid` node's `properties` bag is the spec's
+ * `ComponentPropsMap['object-grid']` row by reference (objectui#11276), and that row still
+ * declared the alias, so a local retirement alone would have left the bag accepting a key
+ * nothing read. `@objectstack/spec` 17.7.0 (objectstack#21445) retired it in the row, and
+ * objectui resolves 17.7.0 since objectui#11717. So this round makes the four strokes:
+ *
+ *   - `resizableColumns?: never` on the interface;
+ *   - a `retirementTombstone()` on the flat zod mirror, naming `properties.resizable`;
+ *   - `ObjectGrid`'s `resizable ?? resizableColumns` fallback read dropped (pinned in
+ *     `@object-ui/plugin-grid`, `ObjectGrid.resizableColumnsRetired-6152.test.tsx`);
+ *   - the key off `zod-mirror-parity.test.ts`'s `UnmirroredDeclared` (its entry went with
+ *     it: a tombstone is a mirrored member).
+ *
+ * The protocol block below is the precondition, re-read against the INSTALLED spec: the
+ * local tombstone must never refuse what the installed protocol accepts.
+ */
+import { describe, it, expect } from 'vitest';
+
+import { ObjectGridPropsSchema as SpecObjectGridPropsSchema } from '@objectstack/spec/ui';
+import type { ObjectGridSchema as TsObjectGridSchema } from '../objectql';
+import { ObjectGridSchema, ObjectViewSchema } from '../zod/objectql.zod.js';
+import { AnyComponentSchema, StrictAnyComponentSchema, safeValidateSchema } from '../zod/index.zod.js';
+
+type Issue = { code: string; path: PropertyKey[]; message: string };
+type Parsed = { success: boolean; error?: { issues: readonly Issue[] } };
+type Parse = (doc: unknown) => Parsed;
+
+const codeAndPath = (r: Parsed) => (r.success ? [] : r.error!.issues.map((i) => ({ code: i.code, path: i.path })));
+
+const GRID = { type: 'object-grid', objectName: 'task' };
+const AUTHORED = { type: 'object-grid', properties: { objectName: 'task' } };
+const VIEW = { type: 'object-view', objectName: 'task' };
+
+const DOORS: ReadonlyArray<readonly [string, Parse]> = [
+  ['the tolerant face', (d) => AnyComponentSchema.safeParse(d)],
+  ['the strict face', (d) => StrictAnyComponentSchema.safeParse(d)],
+  ['safeValidateSchema', (d) => safeValidateSchema(d)],
+];
+
+describe('objectui#6152 round 7 — the installed protocol refuses `resizableColumns` (the precondition)', () => {
+  it('the `object-grid` row refuses `resizableColumns` by name, and takes `resizable`', () => {
+    expect(codeAndPath(SpecObjectGridPropsSchema.safeParse({ resizableColumns: false })))
+      .toEqual([{ code: 'invalid_type', path: ['resizableColumns'] }]);
+    // Lit control: the canonical spelling parses on the same row.
+    expect(SpecObjectGridPropsSchema.safeParse({ resizable: false }).success).toBe(true);
+  });
+});
+
+describe('objectui#6152 round 7 — the flat `ObjectGridSchema` mirror refuses the retired spelling', () => {
+  it('CONTROL: the minimal node and the canonical `resizable` parse', () => {
+    expect(ObjectGridSchema.safeParse(GRID).success).toBe(true);
+    expect(ObjectGridSchema.safeParse({ ...GRID, resizable: false }).success).toBe(true);
+  });
+
+  it('`resizableColumns` is a MEMBER, so `.passthrough()` no longer keeps it unexamined', () => {
+    expect('resizableColumns' in ObjectGridSchema.shape).toBe(true);
+  });
+
+  it.each([true, false])('`resizableColumns: %s` is refused at the key, naming `properties.resizable`', (value) => {
+    const r = ObjectGridSchema.safeParse({ ...GRID, resizableColumns: value });
+    expect(codeAndPath(r)).toEqual([{ code: 'invalid_type', path: ['resizableColumns'] }]);
+    expect(r.success ? '' : r.error.issues[0].message).toContain('properties.resizable');
+  });
+});
+
+describe('objectui#6152 round 7 — every authored door refuses it, flat and in the bag', () => {
+  describe.each(DOORS)('%s', (_door, parse) => {
+    it('CONTROL: `properties.resizable` parses', () => {
+      const r = parse({ ...AUTHORED, properties: { objectName: 'task', resizable: false } });
+      expect(r.success, JSON.stringify(codeAndPath(r))).toBe(true);
+    });
+
+    it('`properties.resizableColumns` is refused at its path', () => {
+      expect(codeAndPath(parse({ ...AUTHORED, properties: { objectName: 'task', resizableColumns: false } })))
+        .toEqual([{ code: 'invalid_type', path: ['properties', 'resizableColumns'] }]);
+    });
+
+    it('a flat `resizableColumns` on the node is refused by name', () => {
+      expect(codeAndPath(parse({ ...AUTHORED, resizableColumns: false })))
+        .toEqual([{ code: 'invalid_type', path: ['resizableColumns'] }]);
+    });
+
+    it('an `object-view` `table.resizableColumns` stays refused by the slot\'s own message', () => {
+      // The slot overrides the grid's tombstone with its own refusal (objectui#10976),
+      // as it does for the five tombstones objectui#11068 retired on the grid.
+      const r = parse({ ...VIEW, table: { resizableColumns: false } });
+      expect(codeAndPath(r)).toEqual([{ code: 'invalid_type', path: ['table', 'resizableColumns'] }]);
+      expect(r.success ? '' : r.error!.issues[0].message).toContain('objectui#10976');
+      // Lit control: the slot relays `resizable`.
+      expect(parse({ ...VIEW, table: { resizable: false } }).success).toBe(true);
+    });
+  });
+
+  it('the `object-view` mirror\'s own slot agrees with the doors above', () => {
+    expect(codeAndPath(ObjectViewSchema.safeParse({ ...VIEW, table: { resizableColumns: false } })))
+      .toEqual([{ code: 'invalid_type', path: ['table', 'resizableColumns'] }]);
+  });
+});
+
+describe('objectui#6152 round 7 — the TypeScript face', () => {
+  it('`resizableColumns` is a `tsc` error on the interface, while `resizable` type-checks', () => {
+    // A real directive: this package type-checks its tests (`tsconfig.test.json`), so a
+    // re-declared member fails on the unused directive.
+    // @ts-expect-error `resizableColumns` is RETIRED (objectui#6152) — write `resizable`
+    const retired: TsObjectGridSchema = { type: 'object-grid', objectName: 'task', resizableColumns: false };
+    const live: TsObjectGridSchema = { type: 'object-grid', objectName: 'task', resizable: false };
+    expect([retired.type, live.resizable]).toEqual(['object-grid', false]);
+  });
+});
+
+/*
+ * Read off the member: a deletion would not compile here at all, and a re-declared
+ * `boolean` would read as `boolean | undefined`.
+ */
+type Equal<A, B> = (<T>() => T extends A ? 1 : 2) extends (<T>() => T extends B ? 1 : 2) ? true : false;
+type Expect<T extends true> = T;
+
+export type assertionResizableColumnsIsRetiredOnTheInterface = [
+  Expect<Equal<TsObjectGridSchema['resizableColumns'], undefined>>,
+  Expect<Equal<TsObjectGridSchema['resizable'], boolean | undefined>>,
+];