fix(workbench): restore focus on a second Alt and keep closed menus closed

src/workbench/MainMenu.interaction.test.tsx

@@ -156,6 +156,45 @@ describe("main menu presentation", () => {
     expect(editor).toHaveFocus();
   });
 
+  it("returns focus on a second lone Alt", async () => {
+    setStyle("merged");
+    render(
+      <>
+        <button>Editor</button>
+        <MainMenu />
+      </>,
+    );
+    await screen.findByRole("menubar");
+    const editor = screen.getByRole("button", { name: "Editor" });
+    editor.focus();
+    alt();
+    expect(titles().getByRole("menuitem", { name: "File" })).toHaveFocus();
+    alt();
+    expect(editor).toHaveFocus();
+    alt();
+    fireEvent.keyDown(document.activeElement!, { key: "Escape" });
+    expect(editor).toHaveFocus();
+  });
+
+  it("does not reopen a title's menu after the titles collapse and return", async () => {
+    setStyle("merged");
+    render(<MainMenu />);
+    await screen.findByRole("menubar");
+    fireEvent.click(titles().getByRole("menuitem", { name: "Edit" }));
+    expect(await screen.findByRole("menu", { name: "Edit" })).toBeInTheDocument();
+    act(() => {
+      available = 100;
+      resize();
+    });
+    expect(screen.queryByRole("menu")).toBeNull();
+    act(() => {
+      available = 500;
+      resize();
+    });
+    expect(screen.getByRole("menubar")).toBeInTheDocument();
+    expect(screen.queryByRole("menu")).toBeNull();
+  });
+
   it("falls back to a hamburger popup when narrow and restores titles when space returns", async () => {
     available = 100;
     setStyle("merged");

src/workbench/MainMenu.tsx

@@ -122,7 +122,13 @@ function MainMenuBar({ merged, onExpandedChange }: MainMenuProps & { merged: boo
   // Measuring the allocated slot includes all neighbouring toolbar/caption controls.
   useLayoutEffect(() => {
     if (!merged || !slot.current || !measure.current) return;
-    const update = () => setFits(menus.length > 0 && slot.current!.clientWidth >= measure.current!.scrollWidth);
+    const update = () => {
+      const next = menus.length > 0 && slot.current!.clientWidth >= measure.current!.scrollWidth;
+      setFits(next);
+      // Each presentation's menu closes with it, and must not reopen when it returns.
+      if (next) setExpanded(false);
+      else setOpen(null);
+    };
     const observer = new ResizeObserver(update);
     observer.observe(slot.current);
     observer.observe(measure.current);
@@ -161,8 +167,11 @@ function MainMenuBar({ merged, onExpandedChange }: MainMenuProps & { merged: boo
         close();
         if (persistent) focusTitle(focused);
       } else if (persistent) {
-        previousFocus.current = document.activeElement as HTMLElement;
-        focusTitle(0);
+        if (bar?.contains(document.activeElement)) previousFocus.current?.focus();
+        else {
+          previousFocus.current = document.activeElement as HTMLElement;
+          focusTitle(0);
+        }
       } else void expand();
     }),
   );