test(ui): a self-closing dialog leaves the focus in a menu that stays open

frontend/src/components/ui/Modal.dom.test.tsx

@@ -375,6 +375,36 @@ describe("Modal focus trap (offsetParent stubbed 'visible')", () => {
     document.body.removeChild(portal);
   });
 
+  it("does not pull the focus out of a menu that stays open when it closes on its own", () => {
+    // The other side of counting a menu row as held: a menu that is NOT this dialog's — a page's
+    // "…" left open while a dialog finishes in the background — stays standing, and a dialog that
+    // closes on its own (a write's success) must not take the focus from it to its trigger.
+    const trigger = document.createElement("button");
+    document.body.appendChild(trigger);
+    trigger.focus();
+    const portal = document.createElement("div");
+    portal.setAttribute("data-floating-ui-portal", "");
+    const row = document.createElement("button");
+    row.textContent = "page-menu-row";
+    portal.appendChild(row);
+    document.body.appendChild(portal);
+    function SelfClosing() {
+      const [open, setOpen] = useState(true);
+      return open ? (
+        <Modal initialFocus="close" title="t" onClose={() => {}}>
+          <button onClick={() => setOpen(false)}>finish</button>
+        </Modal>
+      ) : null;
+    }
+    render(<SelfClosing />);
+    row.focus();
+    act(() => void screen.getByText("finish").click()); // `.click()` moves no focus
+    expect(screen.queryByText("finish")).toBeNull();
+    expect(document.activeElement).toBe(row);
+    document.body.removeChild(trigger);
+    document.body.removeChild(portal);
+  });
+
   it("leaves the focus alone when the user moved it out of the dialog themselves", () => {
     // The other half of the same rule, and the branch nothing drove: taking focus back from where
     // the user deliberately put it is the rudest thing a closing dialog can do.