fix: preserve hidden tool visibility

src/App.test.tsx

@@ -124,6 +124,34 @@ describe('portal UI', () => {
     ).not.toBeInTheDocument();
   });
 
+  it('keeps remaining hidden tools visible while editing the hidden set', async () => {
+    vi.stubGlobal('fetch', vi.fn(catalogueFetch()));
+    const user = userEvent.setup();
+    render(<App />);
+    await screen.findByRole('heading', { name: 'PDF Workbench' });
+
+    await user.click(
+      screen.getByRole('button', { name: 'Hide PDF Workbench' })
+    );
+    const showHidden = screen.getByRole('checkbox', {
+      name: 'Show hidden (1)',
+    });
+    await user.click(showHidden);
+    await user.click(
+      screen.getByRole('button', { name: 'Hide XSLT Workbench' })
+    );
+    expect(showHidden).toHaveAccessibleName('Show hidden (2)');
+    await user.click(
+      screen.getByRole('button', { name: 'Show PDF Workbench' })
+    );
+
+    expect(showHidden).toBeChecked();
+    expect(showHidden).toHaveAccessibleName('Show hidden (1)');
+    expect(
+      screen.getByRole('heading', { name: 'XSLT Workbench' })
+    ).toBeInTheDocument();
+  });
+
   it('clears search filters without revealing hidden tools', async () => {
     vi.stubGlobal('fetch', vi.fn(catalogueFetch()));
     const user = userEvent.setup();

src/App.tsx

@@ -123,7 +123,8 @@ export default function App() {
   const [preferences, setPreferences, storageAvailable] = usePreferences();
   const closeHelp = useCallback(() => setHelpOpen(false), []);
   const showHidden =
-    preferences.hidden.length > 0 && shownHiddenIds === preferences.hidden;
+    preferences.hidden.length > 0 &&
+    shownHiddenIds?.some((id) => preferences.hidden.includes(id)) === true;
   const sensors = useSensors(
     useSensor(PointerSensor, { activationConstraint: { distance: 8 } }),
     useSensor(KeyboardSensor, { coordinateGetter: sortableKeyboardCoordinates })
@@ -205,6 +206,9 @@ export default function App() {
   }));
 
   function toggleListItem(field: 'pinned' | 'hidden', id: string) {
+    if (field === 'hidden' && showHidden && !preferences.hidden.includes(id)) {
+      setShownHiddenIds((current) => [...new Set([...(current ?? []), id])]);
+    }
     setPreferences((current) => ({
       ...current,
       [field]: current[field].includes(id)
@@ -332,7 +336,7 @@ export default function App() {
                     disabled={preferences.hidden.length === 0}
                     onChange={(event) =>
                       setShownHiddenIds(
-                        event.target.checked ? preferences.hidden : null
+                        event.target.checked ? [...preferences.hidden] : null
                       )
                     }
                   />