fix(player): the card under the big view is out of the Tab order, and the focus leaves it and comes back

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

@@ -5,7 +5,7 @@
 import { useRef } from "react";
 import { afterEach, describe, expect, it, vi } from "vitest";
 import { cleanup, render } from "@testing-library/react";
-import { useDialogChrome } from "./dialogFocus";
+import { focusablesIn, useDialogChrome } from "./dialogFocus";
 
 afterEach(cleanup);
 
@@ -36,6 +36,25 @@ describe("useDialogChrome · the page scroll lock", () => {
   });
 });
 
+describe("focusablesIn", () => {
+  // A trap that counted them had its "last" control where Tab never lands, and let the focus out.
+  it("leaves out what an inert part holds", () => {
+    const offsetParent = vi
+      .spyOn(HTMLElement.prototype, "offsetParent", "get")
+      .mockReturnValue(document.body);
+    const { container } = render(
+      <div>
+        <button>reachable</button>
+        <div inert>
+          <button>under</button>
+        </div>
+      </div>,
+    );
+    expect(focusablesIn(container).map((el) => el.textContent)).toEqual(["reachable"]);
+    offsetParent.mockRestore();
+  });
+});
+
 describe("useDialogChrome · initial focus", () => {
   it("lands on the first control by default", () => {
     // jsdom has no layout, so the visibility filter (offsetParent) would see nothing focusable.

frontend/src/components/ui/dialogFocus.ts

@@ -9,12 +9,15 @@ import { useEffect, useEffectEvent, useRef, useState, type RefObject } from "rea
 
 // Tabbable elements inside the dialog, in DOM order. `:not([tabindex="-1"])` drops programmatically
 // focusable-only nodes; the visibility filter (offsetParent) drops display:none ones (e.g. a
-// collapsed disclosure) so the trap never lands focus on something the user can't see.
+// collapsed disclosure) so the trap never lands focus on something the user can't see, and an inert
+// part's are not tabbable: counted, the trap's last control is one Tab never reaches.
 const FOCUSABLE =
   'a[href], button:not([disabled]), textarea:not([disabled]), input:not([disabled]), select:not([disabled]), [tabindex]:not([tabindex="-1"])';
 
 export const focusablesIn = (root: HTMLElement): HTMLElement[] =>
-  [...root.querySelectorAll<HTMLElement>(FOCUSABLE)].filter((el) => el.offsetParent !== null);
+  [...root.querySelectorAll<HTMLElement>(FOCUSABLE)].filter(
+    (el) => el.offsetParent !== null && !el.closest("[inert]"),
+  );
 
 /** A form's first field — where a dialog opened to fill something in takes the focus: its first
  *  control, unless one is marked `data-initial-focus`. The mark is for a form with a control above

frontend/src/features/player/PlayerModal.dom.test.tsx

@@ -1699,6 +1699,64 @@ describe("PlayerModal — the docked bar's fullscreen", () => {
   });
 });
 
+// The big view covers the card, and its controls stayed in the Tab order under it: past the bar's
+// last button the focus went on, unseen, to the card's Previous, Download and Remove.
+describe("PlayerModal — the card under the big view", () => {
+  const open = () => {
+    vi.spyOn(api, "videoDetail").mockReturnValue(new Promise(() => {}));
+    const A = vid("A", 0);
+    renderModal(
+      <PlayerModal
+        video={A}
+        queue={[A]}
+        startIndex={0}
+        onClose={() => {}}
+        onState={() => Promise.resolve()}
+      />,
+    );
+    return screen.getByLabelText("player.fullscreen");
+  };
+
+  it("takes the card out of reach while the view is big, and gives it back", () => {
+    const enter = open();
+    expect(enter.closest("[inert]")).toBeNull();
+    fireEvent.click(enter);
+    expect(enter.closest("[inert]")).not.toBeNull();
+    fireEvent.keyDown(window, { key: "Escape" });
+    expect(enter.closest("[inert]")).toBeNull();
+  });
+
+  it("walks a keyboard from the card's button to the way out, and back to where it was", () => {
+    const enter = open();
+    act(() => enter.focus()); // jsdom calls every focus :focus-visible — a key's focus, here
+    fireEvent.click(enter);
+    expect(document.activeElement).toBe(screen.getByLabelText("player.exitMaximize"));
+    fireEvent.click(screen.getByLabelText("player.exitMaximize"));
+    expect(document.activeElement).toBe(enter);
+  });
+
+  it("does not leave a mouse on the way out, where a Space would leave the big view", () => {
+    const enter = open();
+    act(() => enter.focus());
+    const matches = vi.spyOn(enter, "matches").mockReturnValue(false);
+    fireEvent.click(enter);
+    matches.mockRestore();
+    const card = screen.getByRole("dialog").querySelector<HTMLElement>("[tabindex='-1']");
+    expect(document.activeElement).toBe(card);
+    fireEvent.click(screen.getByLabelText("player.exitMaximize"));
+    expect(document.activeElement).toBe(card);
+  });
+
+  it("does not strand the focus on the page when the bar goes with it", () => {
+    const enter = open();
+    fireEvent.click(enter);
+    act(() => screen.getByLabelText("player.exitMaximize").focus());
+    fireEvent.keyDown(window, { key: "Escape" });
+    expect(document.activeElement).not.toBe(document.body);
+    expect(screen.getByRole("dialog").contains(document.activeElement)).toBe(true);
+  });
+});
+
 // Clip mode: the panel sits under the video (the video is its preview), Escape closes the panel and
 // not the player, the scissors gets the focus back; in the maximised view the panel takes the docked
 // bar's place; a crop frame lies over the video and Escape turns it off before the panel closes.

frontend/src/features/player/PlayerModal.tsx

@@ -450,7 +450,8 @@ export default function PlayerModal({
   // above it ends there.
   const clipDockRef = useRef<HTMLDivElement>(null);
   const [clipDockH, setClipDockH] = useState(0);
-  const clipDocked = clipOpen && (maximized || isFullscreen);
+  const bigView = maximized || isFullscreen;
+  const clipDocked = clipOpen && bigView;
   // Its two places are two parents (the dock is IN the stage, the card's slot under it), and a panel
   // rendered in the other one is a new panel: the typed name, Loop and the focus were lost on every
   // F. So it renders once, into a host node of its own, and the host moves between the two.
@@ -533,14 +534,37 @@ export default function PlayerModal({
     const lost = document.activeElement == null || document.activeElement === document.body;
     if (!refocusClip.current && !lost) return;
     refocusClip.current = false;
-    const big = maximized || isFullscreen;
+    const target = bigView ? clipDockButtonRef.current : clipButtonRef.current;
-    const target = big ? clipDockButtonRef.current : clipButtonRef.current;
     if (target) target.focus();
     else focusModal();
   });
   useEffect(() => {
     if (!clipOpen) refocusAfterClip();
   }, [clipOpen]);
+  // The big view covers the card, so the card's part with the controls goes inert under it (see the
+  // markup) and the focus cannot stay there. A key's focus moves to the way out and comes back to
+  // the same control when the view ends. A mouse's goes to the card: on the way out, the next Space
+  // would leave the big view instead of pausing. A focus the view's end took with it (the bar's
+  // controls go with the bar) goes back to the card. After the clip panel's move above, which keeps
+  // its own focus.
+  const cardPanelRef = useRef<HTMLDivElement>(null);
+  const bigExitRef = useRef<HTMLButtonElement>(null);
+  const focusBeforeBig = useRef<HTMLElement | null>(null);
+  useLayoutEffect(() => {
+    if (bigView) {
+      const active = document.activeElement;
+      if (!(active instanceof HTMLElement) || !cardPanelRef.current?.contains(active)) return;
+      const byKey = active.matches(":focus-visible");
+      focusBeforeBig.current = byKey ? active : null;
+      if (byKey && bigExitRef.current) bigExitRef.current.focus();
+      else focusModal();
+      return;
+    }
+    const back = focusBeforeBig.current;
+    focusBeforeBig.current = null;
+    if (back?.isConnected) back.focus();
+    else reclaimFocus();
+  }, [bigView, focusModal, reclaimFocus]);
   /** Mark where the player is now (`mark` gets the range so far, or null when the panel is shut). The
    *  panel lives under the video in the card, and in place of the docked bar when maximised; the
    *  browser's fullscreen steps back to the maximised view, which has room for it. */
@@ -1151,7 +1175,7 @@ export default function PlayerModal({
               which would drop any class on mountRef itself — the iframe then sizes to this wrapper. */}
               <div
                 className={
-                  maximized || isFullscreen
+                  bigView
                     ? `absolute inset-x-0 top-0 ${clipDocked ? "" : "bottom-14"}`
                     : "relative w-full h-full"
                 }
@@ -1209,7 +1233,7 @@ export default function PlayerModal({
               {clipDocked && (
                 <div ref={clipDockRef} className="absolute inset-x-0 bottom-0 z-menu" />
               )}
-              {(maximized || isFullscreen) && !clipDocked && (
+              {bigView && !clipDocked && (
                 <div
                   onClick={(e) => e.stopPropagation()}
                   className="absolute inset-x-0 bottom-0 z-menu flex h-14 items-center gap-x-3 border-t border-white/10 bg-media-chrome/95 media-marks px-3 text-sm text-white"
@@ -1287,6 +1311,7 @@ export default function PlayerModal({
                     </IconButton>
                   )}
                   <IconButton
+                    ref={bigExitRef}
                     variant="overlay"
                     onClick={(e) => {
                       e.stopPropagation();
@@ -1356,6 +1381,8 @@ export default function PlayerModal({
           {/* Wide: the side panel. Its content scrolls inside a box the video's height, so a long
             description never makes the card taller than the video. */}
           <div
+            ref={cardPanelRef}
+            inert={bigView}
             className={wide ? "relative shrink-0 border-l border-border" : undefined}
             style={wide ? { width: panelWidth } : undefined}
           >