diff --git a/CHANGELOG.md b/CHANGELOG.md
index e45f1465..13b4aef4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -325,8 +325,21 @@ auto-generated per-PR notes; this file is the curated, human-readable history.
   builders. The Dashboard File trigger now uses the same downward-chevron
   treatment as Workbench (no more right-arrow that misread as navigation) and
   its menu gains EXPORT/IMPORT/OPEN section headings, icons, and `.json`
-  metadata; read-only Dashboards still expose Export only. Actions and
-  permission rules are unchanged.
+  metadata; read-only Dashboards expose Export only at this point (superseded
+  by #347, below). Actions and permission rules are unchanged.
+- **Read-only Dashboard views (detached current-workspace and one-time
+  session-bundle) no longer render a File menu at all** (#347). The prior
+  read-only behavior above (#331) still showed an Export button, but
+  `exportDashboardAction` resolves the latest **committed primary** workspace
+  via `app.workspace.loadCurrent()` — in a read-only route that primary
+  workspace can be unrelated to the Dashboard actually on screen, so clicking
+  Export could silently download the wrong (and potentially private) Dashboard
+  and its queries. `buildDashboardFileMenu` no longer takes a `readOnly` flag;
+  the caller now omits the button/menu from the DOM entirely — never disabled
+  or visually hidden — when the resolved route is read-only, keeping keyboard
+  tab order and the accessibility tree free of an inoperable control. Editable
+  current-workspace Dashboards are unaffected and keep the full
+  Export/Import/Open-for-viewing menu.
 - **Dashboard tile content stays inside the tile body, above the footer**
   (#331). `.dash-tile-body` gained `overflow:hidden`, and the tall-panel
   containment contract (`flex:1 1 auto; min-width/min-height:0; max-height:100%;
diff --git a/src/ui/dashboard.ts b/src/ui/dashboard.ts
index d6b427c7..44b5a90e 100644
--- a/src/ui/dashboard.ts
+++ b/src/ui/dashboard.ts
@@ -268,17 +268,21 @@ function renderDashboardNotFound(app: DashboardApp): void {
  *    EXPORT   ⭳ Export Dashboard…   .json
  *    IMPORT   ⭱ Import Dashboard…
  *    OPEN     ◇ Open for viewing…
- *  Edit mode offers all three sections; a read-only (detached) view offers
- *  EXPORT only (import + re-preview are edit-context operations). Every item
- *  delegates to an `app.actions.*` seam (dashboard.ts never reaches into
- *  app.ts). The trigger uses the shared downward-chevron treatment
- *  (`Icon.chevDown()`, matching the Workbench File button) rather than a
- *  right-pointing arrow, which would misread as navigation. The trigger owns
- *  its own open/close TOGGLE (unlike the Workbench menu, which only ever
- *  opens) — clicking it again while open closes the menu and restores focus,
- *  tracked here via the returned `MenuHandle` rather than a second
- *  `openMenu` call. */
-function buildDashboardFileMenu(app: DashboardApp, readOnly: boolean): HTMLElement {
+ *  #347: only ever built for an EDITABLE (non-read-only) Dashboard — the
+ *  caller omits the control entirely for a read-only route. (Previously a
+ *  read-only view got an Export-only menu, but `exportDashboardAction`
+ *  resolves the latest COMMITTED PRIMARY workspace via `workspace.loadCurrent()`,
+ *  which may be unrelated to the read-only Dashboard on screen; hiding rows
+ *  wasn't enough, since the surviving Export button still exported the wrong
+ *  workspace.) Every item delegates to an `app.actions.*` seam (dashboard.ts
+ *  never reaches into app.ts). The trigger uses the shared downward-chevron
+ *  treatment (`Icon.chevDown()`, matching the Workbench File button) rather
+ *  than a right-pointing arrow, which would misread as navigation. The
+ *  trigger owns its own open/close TOGGLE (unlike the Workbench menu, which
+ *  only ever opens) — clicking it again while open closes the menu and
+ *  restores focus, tracked here via the returned `MenuHandle` rather than a
+ *  second `openMenu` call. */
+function buildDashboardFileMenu(app: DashboardApp): HTMLElement {
   const doc = app.document;
   const btn = h('button', {
     class: 'dash-btn dash-file-btn', 'aria-haspopup': 'menu', 'aria-expanded': 'false',
@@ -294,21 +298,17 @@ function buildDashboardFileMenu(app: DashboardApp, readOnly: boolean): HTMLEleme
         kind: 'item', icon: Icon.download(), label: 'Export Dashboard…', meta: '.json', extraClass: 'dash-fm-item',
         onClick: () => app.actions.exportDashboard(),
       },
+      { kind: 'section', label: 'Import' },
+      {
+        kind: 'item', icon: Icon.upload(), label: 'Import Dashboard…', extraClass: 'dash-fm-item',
+        onClick: () => app.actions.importDashboard(),
+      },
+      { kind: 'section', label: 'Open' },
+      {
+        kind: 'item', icon: Icon.eye(), label: 'Open for viewing…', extraClass: 'dash-fm-item',
+        onClick: () => app.actions.openDashboardForViewing(),
+      },
     ];
-    if (!readOnly) {
-      rows.push(
-        { kind: 'section', label: 'Import' },
-        {
-          kind: 'item', icon: Icon.upload(), label: 'Import Dashboard…', extraClass: 'dash-fm-item',
-          onClick: () => app.actions.importDashboard(),
-        },
-        { kind: 'section', label: 'Open' },
-        {
-          kind: 'item', icon: Icon.eye(), label: 'Open for viewing…', extraClass: 'dash-fm-item',
-          onClick: () => app.actions.openDashboardForViewing(),
-        },
-      );
-    }
     handle = openMenu({
       document: doc, trigger: btn, rows, menuClass: 'dash-file-menu',
       onClose: () => { handle = null; },
@@ -553,8 +553,10 @@ export async function renderDashboard(app: DashboardApp): Promise<void> {
   const showLayoutSelect = !readOnly || currentDoc.layout.type === 'grafana-grid';
 
   // #302: the Dashboard page's own resource-scoped File menu (import/export +
-  // open-for-viewing).
-  const fileMenuBtn = buildDashboardFileMenu(app, readOnly);
+  // open-for-viewing). #347: omitted from the DOM entirely in a read-only
+  // view — not merely disabled/hidden — so keyboard tab order and the
+  // accessibility tree carry no File control where no operation is valid.
+  const fileMenuBtn = readOnly ? null : buildDashboardFileMenu(app);
   const header = h('div', { class: 'dash-header' },
     h('a', {
       class: 'dash-back', href: app.conn.basePath || '/sql', title: 'Back to SQL Browser', 'aria-label': 'Back to SQL Browser',
diff --git a/tests/unit/dashboard.test.ts b/tests/unit/dashboard.test.ts
index 31f02b72..9f530c4d 100644
--- a/tests/unit/dashboard.test.ts
+++ b/tests/unit/dashboard.test.ts
@@ -3044,13 +3044,42 @@ describe('renderDashboard — Dashboard header File menu (#302)', () => {
     expect(document.querySelector('.dash-file-menu')).toBeNull();
   });
 
-  it('view mode: the File menu offers Export only (import + re-preview are edit-context)', async () => {
+  it('editable current-workspace mode includes the File button (#347)', async () => {
+    const { app } = editApp();
+    await render(app);
+    expect(qs(app.root, '.dash-file-btn')).not.toBeNull();
+  });
+
+  it('detached view mode omits the File button entirely, not just its Import/Open rows (#347)', async () => {
     const detached = wsWith({ id: 'd', queries: [q('q1', 'SELECT 1')], tiles: [{ id: 't1', queryId: 'q1' }] });
     const { app } = modeApp({ workspace: null, detached, openSource: { kind: 'current-workspace', workspaceId: 'w', dashboardId: 'd' } });
     await render(app);
-    openFileMenuBtn(app.root);
-    expect(menuSections()).toEqual(['Export']);
-    expect(menuItems()).toEqual(['Export Dashboard…']);
+    expect(qs(app.root, '.dash-file-btn')).toBeNull();
+    expect(document.querySelector('.dash-file-menu')).toBeNull();
+  });
+
+  it('session-bundle read-only mode omits the File button entirely (#347)', async () => {
+    const detached = wsWith({ id: 'd', queries: [q('q1', 'SELECT 1')], tiles: [{ id: 't1', queryId: 'q1' }] });
+    const consume = vi.fn(async () => detached as never);
+    const { app } = modeApp({ openSource: { kind: 'session-bundle', token: 'tok', dashboardId: 'd' }, consume });
+    await render(app);
+    expect(qs(app.root, '.dash-file-btn')).toBeNull();
+  });
+
+  it('a different primary workspace existing cannot export it from the read-only page (#347)', async () => {
+    // The primary store holds an UNRELATED dashboard ('other') — resolveDashboardMode
+    // won't match it against this route's `dashboardId: 'd'`, so it falls through to
+    // the detached store, same as production when a primary workspace exists but this
+    // tab is showing someone else's shared/detached Dashboard.
+    const primary = wsWith({ id: 'other', queries: [q('secret', 'SELECT 2')], tiles: [{ id: 'ts', queryId: 'secret' }] });
+    const detached = wsWith({ id: 'd', queries: [q('q1', 'SELECT 1')], tiles: [{ id: 't1', queryId: 'q1' }] });
+    const { app } = modeApp({ workspace: primary, detached, openSource: { kind: 'current-workspace', workspaceId: 'w', dashboardId: 'd' } });
+    await render(app);
+    expect(qs(app.root, '.dash-notfound')).toBeNull();
+    // No File control at all — no way to reach exportDashboard() (which reads
+    // the PRIMARY workspace via app.workspace.loadCurrent(), i.e. `primary` here)
+    // from this read-only page.
+    expect(qs(app.root, '.dash-file-btn')).toBeNull();
   });
 
   it('an unrelated keydown while the menu is open is ignored', async () => {