fix(ui): a closing dialog's focus restore reaches the dialog left standing above it, and survives a menu

A dialog closing on its own under a standing modal skipped its restore, and the standing modal's
own target was a control inside the closed one: closing it left the focus on <body>. The skipped
target is now handed to the standing dialog, which falls back to it.

Focus on a row of one of the dialog's own menus (the popover engine portals them out of the dialog
root) read as the user walking away, so Back with a menu open left the focus on <body>. A focus in
a popover portal now counts as held, and one still standing is not taken from.

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

@@ -23,7 +23,7 @@ vi.mock("../../lib/history", () => ({ useBackToClose: () => {} }));
 import Modal from "./Modal";
 import { clearAll, notify } from "../../lib/notifications";
 import { pushLayer, removeLayer, useLayer } from "../../lib/layerStack";
-import { flushSync } from "react-dom";
+import { createPortal, flushSync } from "react-dom";
 
 // Fire a keydown on window (where Modal installs its handler), inside act.
 const press = (key: string, shiftKey = false) =>
@@ -311,6 +311,70 @@ describe("Modal focus trap (offsetParent stubbed 'visible')", () => {
     document.body.removeChild(trigger);
   });
 
+  it("hands its trigger to the dialog left standing above it, which restores it on close", () => {
+    // The standing upper dialog captured ITS restore target while the focus was inside the lower
+    // one — a control that is gone once the lower closes. So the lower skipping its own restore
+    // (above) handed the trigger to no one, and closing the upper left the focus on <body>.
+    // The arrangement keyboard help or the error dialog opened over a dialog actually has.
+    const trigger = document.createElement("button");
+    document.body.appendChild(trigger);
+    trigger.focus();
+    function Siblings() {
+      const [lower, setLower] = useState(true);
+      const [upper, setUpper] = useState(false);
+      return (
+        <>
+          {lower && (
+            <Modal initialFocus="close" title="lower" onClose={() => {}}>
+              <button onClick={() => setUpper(true)}>open upper</button>
+              <button onClick={() => setLower(false)}>close lower</button>
+            </Modal>
+          )}
+          {upper && (
+            <Modal initialFocus="close" title="upper" onClose={() => {}}>
+              <button onClick={() => setUpper(false)}>close upper</button>
+            </Modal>
+          )}
+        </>
+      );
+    }
+    render(<Siblings />);
+    screen.getByText("open upper").focus();
+    act(() => void screen.getByText("open upper").click()); // opened from inside the lower dialog
+    const inUpper = screen.getByText("close upper");
+    inUpper.focus();
+    // The lower closes on its own under the standing upper (`.click()` moves no focus).
+    act(() => void screen.getByText("close lower").click());
+    expect(screen.queryByText("close lower")).toBeNull();
+    expect(document.activeElement).toBe(inUpper);
+    act(() => void inUpper.click());
+    expect(document.activeElement).toBe(trigger);
+    document.body.removeChild(trigger);
+  });
+
+  it("restores the trigger when it closes with the focus in one of its menus", () => {
+    // The popover engine portals a menu out of the dialog's root (it carries no aria-modal), so a
+    // focus on a menu row read as "the user walked away": Back with a menu open inside a dialog
+    // left the focus on <body>. The portal marker is the one `ui/AnchoredPopover` reads too.
+    const trigger = document.createElement("button");
+    document.body.appendChild(trigger);
+    trigger.focus();
+    const portal = document.createElement("div");
+    portal.setAttribute("data-floating-ui-portal", "");
+    document.body.appendChild(portal);
+    const { unmount } = render(
+      <Modal initialFocus="close" title="t" onClose={() => {}}>
+        <Body />
+        {createPortal(<button>menu-row</button>, portal)}
+      </Modal>,
+    );
+    screen.getByText("menu-row").focus();
+    unmount();
+    expect(document.activeElement).toBe(trigger);
+    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.

frontend/src/components/ui/dialogFocus.ts

@@ -75,6 +75,16 @@ export function lockBodyScroll(): () => void {
   };
 }
 
+// A popover engine surface (`ui/AnchoredPopover`): portalled out of the dialog's root and carrying no
+// aria-modal, so a focus on one of a dialog's menu rows is inside the dialog all the same.
+const FLOATING = "[data-floating-ui-portal]";
+
+// Restore targets handed to a dialog left standing above one that closed (see the cleanup below):
+// that dialog's own target was captured while the focus was in the one that closed, and is gone.
+// Keyed by the standing dialog's aria-modal element; a WeakMap, so a dialog that never closes
+// through this hook leaves nothing behind.
+const handedRestore = new WeakMap<Element, HTMLElement>();
+
 /** The rest of the contract: lock the page behind, open focused, hand the focus back on close.
  *  `scopeRef` is the panel the focus should land in; `ownerRef`, when the dialog is bigger than its
  *  panel, is that whole dialog — it must be the SAME element `trapTab` is scoped to, or the two
@@ -128,6 +138,11 @@ export function useDialogChrome(
     // Today that reads the same either way (a detached owner and a null one both fail every
     // `contains` below), but the cleanup should not depend on a ref React has already let go of.
     const ownerAtOpen = ownerRef?.current ?? scope;
+    // This dialog's aria-modal element, the key a closing dialog under it hands its target by.
+    const modalAtOpen =
+      ownerAtOpen?.closest('[aria-modal="true"]') ??
+      ownerAtOpen?.querySelector('[aria-modal="true"]') ??
+      null;
     if (scope && !scope.contains(document.activeElement)) {
       const back = focusedRef.current;
       const target =
@@ -144,10 +159,12 @@ export function useDialogChrome(
       // it — and while it held the focus we read that as the user walking away. Then both closing
       // together left the focus on <body>: ours skipped the restore, and the child's own
       // `restoreTo` was already detached (passive cleanups run parent-first). Measured in jsdom,
-      // and it is the ordinary case — an error dialog raised over a dialog.
+      // and it is the ordinary case — an error dialog raised over a dialog. And one of its own
+      // menus (see FLOATING): Back with a menu open closed the dialog with the focus on a menu row.
       heldRef.current =
         (owner?.contains(active) ?? false) ||
-        (active instanceof Element && active.closest('[aria-modal="true"]') != null);
+        (active instanceof Element &&
+          (active.closest('[aria-modal="true"]') != null || active.closest(FLOATING) != null));
       // Where to put the focus back on a re-mount, though: the PANEL's own last focus. A toast is
       // gone by then, so restoring onto it would strand the focus exactly as before.
       if (scopeRef.current?.contains(document.activeElement))
@@ -172,16 +189,28 @@ export function useDialogChrome(
       // this, a dialog closing on its own (an in-flight mutation's `onSuccess`) under a modal raised
       // above it pulled the focus out of that standing dialog onto our own trigger, behind its
       // scrim — where Enter still activated it.
+      //
+      // Skipped, the trigger is handed to that standing dialog instead: ITS target was captured
+      // while the focus was in ours, so it is gone now, and it falls back to the one handed to it.
+      // A popover still standing (a menu of a dialog that stays open) is not ours to take from
+      // either, though there is no dialog to hand the trigger to.
       const owner = ownerAtOpen;
       const active = document.activeElement;
+      const target = restoreTo?.isConnected
+        ? restoreTo
+        : modalAtOpen
+          ? handedRestore.get(modalAtOpen)
+          : undefined;
       const above = active instanceof Element ? active.closest('[aria-modal="true"]') : null;
       const standingAbove =
         above !== null &&
         above.isConnected &&
         !above.contains(owner as Node | null) &&
         !(owner?.contains(above) ?? false);
-      if (heldRef.current && !standingAbove && restoreTo && restoreTo.isConnected)
+      const standingMenu = active instanceof Element && active.closest(FLOATING)?.isConnected;
-        restoreTo.focus();
+      if (!heldRef.current || !target?.isConnected) return;
+      if (standingAbove) handedRestore.set(above, target);
+      else if (!standingMenu) target.focus();
     };
   }, [restoreTo, scopeRef, ownerRef, focusScope]);
 }