@@ -0,0 +1,201 @@
+// @vitest-environment jsdom
+import { describe, it, expect, beforeEach, vi } from "vitest";
+import { act, renderHook, waitFor } from "@testing-library/react";
+import { buildMenuModel, type MenuFlags, type HistorySubmenu, type SubmenuLabels } from "../lib/menuModel";
+import { fallbackTranslations as en } from "../locales";
+import type { MenuHandlers, useNativeMenu as nativeMenuHook } from "./useNativeMenu";
+
+interface MockItem {
+  id: string;
+  text?: string;
+  items?: MockItem[];
+  close: () => Promise<void>;
+  setAsAppMenu: () => Promise<void>;
+}
+
+/** Mirrors tauri 2.12.0: `menu/plugin.rs` keys click channels by menu id, the `Drop` in
+ *  `menu/mod.rs` removes one by that id, and `muda` hands out a counter value when no id is given. */
+const tauri = vi.hoisted(() => ({
+  channels: new Map<string, (id: string) => void>(),
+  installed: [] as Record<string, unknown>[],
+  closed: [] as string[],
+  seq: 0,
+}));
+
+vi.mock("../lib/platform", () => ({ isDesktopShell: true, isMacDesktop: false }));
+
+vi.mock("@tauri-apps/api/menu", () => {
+  const create = async (opts: Record<string, unknown> = {}) => {
+    const id = typeof opts.id === "string" ? opts.id : `auto-${tauri.seq++}`;
+    const action = opts.action as ((id: string) => void) | undefined;
+    if (action) tauri.channels.set(id, action);
+    const item = {
+      ...opts,
+      id,
+      close: async () => {
+        tauri.closed.push(id);
+        tauri.channels.delete(id);
+      },
+      setText: async () => undefined,
+      setEnabled: async () => undefined,
+      setChecked: async () => undefined,
+      insert: async () => undefined,
+      removeAt: async () => undefined,
+      setAsAppMenu: async () => {
+        tauri.installed.push(item);
+      },
+    };
+    return item;
+  };
+  const kind = { new: create };
+  return { Menu: kind, Submenu: kind, MenuItem: kind, IconMenuItem: kind, PredefinedMenuItem: kind, CheckMenuItem: kind };
+});
+
+const BASE_FLAGS: MenuFlags = {
+  hasObjects: true,
+  documentEmits: true,
+  sourceEditing: false,
+  canBatchExport: false,
+  batchRowCount: 0,
+  batchPrintCount: 0,
+  connectDataWizard: true,
+  canBatchPdf: false,
+  pdfCurrentPageOnly: false,
+  canUndo: false,
+  canRedo: false,
+  includeQuit: true,
+};
+const BATCH_FLAGS: MenuFlags = { ...BASE_FLAGS, canBatchExport: true, batchRowCount: 3, batchPrintCount: 3 };
+
+const LABELS: SubmenuLabels = { file: "File", edit: "Edit", help: "Help", quit: "Quit" };
+const HISTORY: HistorySubmenu = {
+  label: "History",
+  clearLabel: "Clear history",
+  canClear: true,
+  items: [
+    { index: 0, label: "Add text", current: false, enabled: true },
+    { index: 1, label: "Move text", current: true, enabled: true },
+  ],
+};
+
+const model = (flags: MenuFlags) => buildMenuModel(en, flags);
+
+const spyHandlers = (): MenuHandlers => {
+  const out: Partial<MenuHandlers> = {};
+  const full = model(BATCH_FLAGS);
+  for (const item of [...full.file.flat(), ...full.edit.flat(), ...full.help.flat()]) out[item.id] = vi.fn();
+  return out as MenuHandlers;
+};
+
+const liveItems = (): MockItem[] => {
+  const walk = (items: MockItem[]): MockItem[] => items.flatMap((i) => [i, ...walk(i.items ?? [])]);
+  return walk(((tauri.installed.at(-1) as MockItem | undefined)?.items ?? []));
+};
+
+/** Fires the click the way Rust does, with the item's own id as the payload. */
+const click = (text: string) => {
+  const item = liveItems().find((i) => i.text === text);
+  expect(item, `item "${text}" on the menubar`).toBeTruthy();
+  const channel = tauri.channels.get((item as MockItem).id);
+  expect(channel, `click channel of "${text}"`).toBeTruthy();
+  (channel as (id: string) => void)((item as MockItem).id);
+};
+
+let useNativeMenu: typeof nativeMenuHook;
+
+beforeEach(async () => {
+  tauri.channels.clear();
+  tauri.installed.length = 0;
+  tauri.closed.length = 0;
+  tauri.seq = 0;
+  // The hook keeps the installed tree in module state, so every case starts with no menu.
+  vi.resetModules();
+  ({ useNativeMenu } = await import("./useNativeMenu"));
+});
+
+/** The swap closes the superseded tree without awaiting it, so a click before that is no proof. */
+const swapped = (trees: number) =>
+  waitFor(() => {
+    expect(tauri.installed).toHaveLength(trees);
+    expect(tauri.closed.length).toBeGreaterThan(0);
+  });
+
+interface Rebuilt {
+  handlers: MenuHandlers;
+  onHistoryJump: (index: number) => void;
+  onHistoryClear: () => void;
+  onInitError: () => void;
+}
+
+async function rebuild(next: { flags?: MenuFlags; dark?: boolean }): Promise<Rebuilt> {
+  const handlers = spyHandlers();
+  const onHistoryJump = vi.fn();
+  const onHistoryClear = vi.fn();
+  const onInitError = vi.fn();
+  const { rerender } = renderHook(
+    ({ flags }: { flags: MenuFlags }) =>
+      useNativeMenu(model(flags), LABELS, handlers, {}, HISTORY, onHistoryJump, onHistoryClear, onInitError),
+    { initialProps: { flags: BASE_FLAGS } },
+  );
+  await waitFor(() => expect(tauri.installed).toHaveLength(1));
+  if (next.dark !== undefined) act(() => setDark(next.dark as boolean));
+  rerender({ flags: next.flags ?? BASE_FLAGS });
+  await swapped(2);
+  expect(onInitError).not.toHaveBeenCalled();
+  return { handlers, onHistoryJump, onHistoryClear, onInitError };
+}
+
+/** The jsdom stub in the test setup never changes, so the theme needs its own. */
+let listeners: (() => void)[] = [];
+let darkScheme = false;
+function setDark(dark: boolean) {
+  darkScheme = dark;
+  for (const fire of listeners) fire();
+}
+beforeEach(() => {
+  listeners = [];
+  darkScheme = false;
+  // The hook reads `matches` off the object it subscribed with, so the flag has to be live on it.
+  window.matchMedia = ((query: string) => ({
+    get matches() {
+      return query.includes("dark") && darkScheme;
+    },
+    addEventListener: (_: string, fire: () => void) => listeners.push(fire),
+    removeEventListener: () => undefined,
+  })) as unknown as typeof window.matchMedia;
+});
+
+describe("useNativeMenu after a rebuild", () => {
+  it("keeps every command of the new tree clickable when batch entries change the structure", async () => {
+    const { handlers } = await rebuild({ flags: BATCH_FLAGS });
+
+    click(en.app.newDesign);
+    click(en.app.sendToZebraBatchFmt.replace("{n}", "3"));
+    click(en.app.exportBatchZplFmt.replace("{n}", "3"));
+
+    expect(handlers.new).toHaveBeenCalledOnce();
+    expect(handlers.sendToZebra).toHaveBeenCalledOnce();
+    expect(handlers.exportBatch).toHaveBeenCalledOnce();
+  });
+
+  it("keeps the history submenu clickable too, the steps and the clear entry", async () => {
+    const { onHistoryJump, onHistoryClear } = await rebuild({ flags: BATCH_FLAGS });
+
+    // The steps have no id of their own either since the fix, so they belong in this guard.
+    click("Move text");
+    click("Clear history");
+
+    expect(onHistoryJump).toHaveBeenCalledWith(1);
+    expect(onHistoryClear).toHaveBeenCalledOnce();
+  });
+
+  it("keeps the commands clickable when the OS theme flips", async () => {
+    const { handlers } = await rebuild({ dark: true });
+
+    click(en.app.newDesign);
+    click(en.app.sendToZebra);
+
+    expect(handlers.new).toHaveBeenCalledOnce();
+    expect(handlers.sendToZebra).toHaveBeenCalledOnce();
+  });
+});
@@ -93,8 +93,6 @@ let latest: MenuData | null = null;
 let installed: InstalledMenu | null = null;
 let updateGen = 0;
 let queue: Promise<void> = Promise.resolve();
-/** Unique step ids: positional ids could collide with an item still closing. */
-let stepIdSeq = 0;
 /** The OS toggles a clicked CheckMenuItem's checkmark itself; after a jump we
  *  re-assert every step's checkmark so that stray toggle can't linger. */
 let checkmarkDirty = false;
@@ -143,7 +141,6 @@ async function makeStepItem(
 ): Promise<HistoryStep> {
   const { CheckMenuItem } = await import('@tauri-apps/api/menu');
   const item = await CheckMenuItem.new({
-    id: `history-${stepIdSeq++}`,
     text: step.label,
     checked: step.current,
     enabled: step.enabled,
@@ -171,11 +168,12 @@ async function rebuildMenu(structureKey: string, d: MenuData, gen: number): Prom
 
     const items = new Map<MenuItemId, ItemHandle>();
     const buildItem = async (item: { id: MenuItemId; label: string; enabled: boolean }) => {
+      // Nothing here names a menu item: Tauri keys click channels by menu id and drops one when that
+      // id closes, so a rebuild's old tree would take the new tree's channels. Its own ids are unique.
       const base = {
-        id: item.id,
         text: item.label,
         enabled: item.enabled,
-        action: (id: string) => latest?.handlers[id as MenuItemId]?.(),
+        action: () => latest?.handlers[item.id]?.(),
       };
       const icon = await itemIcon(item.id, d.icons, d.dark);
       const handle = track(icon ? await IconMenuItem.new({ ...base, icon }) : await MenuItem.new(base));
@@ -199,7 +197,6 @@ async function rebuildMenu(structureKey: string, d: MenuData, gen: number): Prom
       steps.push(hstep);
     }
     const clear = track(await MenuItem.new({
-      id: 'historyClear',
       text: d.history.clearLabel,
       enabled: d.history.canClear,
       action: () => latest?.onHistoryClear(),