From 09e7f212b700e037d3b87d2711daec81d3072c3f Mon Sep 17 00:00:00 2001
From: Blomios <blomios@gmail.com>
Date: Sun, 12 Jul 2026 15:08:34 +0200
Subject: [PATCH] =?UTF-8?q?feat(ui):=20refonte=20menus=20&=20fen=C3=AAtres?=
 =?UTF-8?q?=20=E2=80=94=20menu=20unique=20Panneaux=20et=20onglets=20projet?=
 =?UTF-8?q?=20(#26)?=
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Sous-menus flyout dans MenuBar ; ProjectsView expose un menu unique
Panneaux et supprime les menus View/Window/File ainsi que le sélecteur
de projet ; ProjectTabs gère les onglets et le bouton +. Tests migrés
en conséquence.

QA vert : tsc --noEmit exit 0, vitest 62 fichiers / 616 tests passés,
invariants préservés.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 .../src/features/projects/ProjectTabs.tsx     |  49 +++--
 .../projects/ProjectsView.detach.test.tsx     |  47 +++--
 .../projects/ProjectsView.docking.test.tsx    |  21 +-
 .../projects/ProjectsView.ls7.test.tsx        |  18 +-
 .../src/features/projects/ProjectsView.tsx    | 196 ++++++++----------
 .../src/features/projects/projects.test.tsx   |  62 +++---
 frontend/src/shared/ui/MenuBar.tsx            | 129 +++++++++---
 7 files changed, 305 insertions(+), 217 deletions(-)

diff --git a/frontend/src/features/projects/ProjectTabs.tsx b/frontend/src/features/projects/ProjectTabs.tsx
index 33054bb..2bec108 100644
--- a/frontend/src/features/projects/ProjectTabs.tsx
+++ b/frontend/src/features/projects/ProjectTabs.tsx
@@ -1,9 +1,13 @@
 /**
  * `ProjectTabs` — the project tab bar rendered below the app header.
  *
- * Shows one tab per open project with a close control, and a "+" button to
- * return to the launcher.  Purely presentational: all state lives in the
- * parent (ProjectsView via useProjects).
+ * Shows one tab per open project with a close control, and a "+" button to the
+ * right that opens the **Projects** panel (floating) — the single entry point
+ * for creating a project or switching to a known one (#26). Purely
+ * presentational: all state lives in the parent (ProjectsView via useProjects).
+ *
+ * The bar is always present (even with no open project) so the "+" stays
+ * reachable; the empty case shows a muted placeholder next to it.
  */
 
 import type { TabItem } from "@/shared";
@@ -14,9 +18,10 @@ export interface ProjectTabsProps {
   activeTabId: string | null;
   onSelect: (id: string) => void;
   onClose: (id: string) => void;
-  /** Whether the launcher overlay is currently visible (no active tab). */
-  showingLauncher: boolean;
-  onShowLauncher: () => void;
+  /** Whether the Projects panel is currently open (in any placement). */
+  projectsPanelOpen: boolean;
+  /** Open the Projects panel (floating) — create/switch project. */
+  onOpenProjectsPanel: () => void;
   className?: string;
 }
 
@@ -25,31 +30,33 @@ export function ProjectTabs({
   activeTabId,
   onSelect,
   onClose,
-  showingLauncher,
-  onShowLauncher,
+  projectsPanelOpen,
+  onOpenProjectsPanel,
   className,
 }: ProjectTabsProps) {
-  if (items.length === 0) return null;
-
   return (
     <div
       className={cn(
-        "flex items-center gap-1 border-b border-border bg-surface px-2 py-1",
+        "flex shrink-0 items-center gap-1 border-b border-border bg-surface px-2 py-1",
         className,
       )}
     >
-      <Tabs
-        items={items}
-        value={activeTabId}
-        onSelect={onSelect}
-        onClose={onClose}
-        className="flex-1"
-      />
+      {items.length === 0 ? (
+        <p className="flex-1 px-2 text-sm text-muted">No open tabs.</p>
+      ) : (
+        <Tabs
+          items={items}
+          value={activeTabId}
+          onSelect={onSelect}
+          onClose={onClose}
+          className="flex-1"
+        />
+      )}
       <Button
         size="sm"
-        variant={showingLauncher ? "secondary" : "ghost"}
-        onClick={onShowLauncher}
-        aria-label="open project launcher"
+        variant={projectsPanelOpen ? "secondary" : "ghost"}
+        onClick={onOpenProjectsPanel}
+        aria-label="open projects panel"
         className="shrink-0"
       >
         +
diff --git a/frontend/src/features/projects/ProjectsView.detach.test.tsx b/frontend/src/features/projects/ProjectsView.detach.test.tsx
index 92664db..ed5b71f 100644
--- a/frontend/src/features/projects/ProjectsView.detach.test.tsx
+++ b/frontend/src/features/projects/ProjectsView.detach.test.tsx
@@ -49,23 +49,27 @@ async function renderWithProject() {
   return { windowGateway, projectId: created.id };
 }
 
-function openMenuItem(menu: string, item: string) {
-  fireEvent.click(screen.getByRole("button", { name: menu }));
-  fireEvent.click(screen.getByRole("button", { name: item }));
+/**
+ * Picks a placement for a panel from the single « Panneaux » menu (#26): menu →
+ * panel entry (opens its placement submenu) → the placement leaf ("Flottant",
+ * "Ancré à gauche", "Fenêtre détachée", …).
+ */
+function pickPlacement(panelTitle: string, placementLabel: string) {
+  fireEvent.click(screen.getByRole("button", { name: "Panneaux" }));
+  fireEvent.click(screen.getByRole("button", { name: panelTitle }));
+  fireEvent.click(screen.getByRole("button", { name: placementLabel }));
 }
 
 describe("ProjectsView detach to OS window (#23)", () => {
-  it("Window menu detaches a view: opens the OS window and marks the slot detached", async () => {
+  it("« Fenêtre détachée » detaches a view: opens the OS window and marks the slot detached", async () => {
     const { windowGateway, projectId } = await renderWithProject();
 
     // A docked view is visible in the main window first…
-    openMenuItem("View", "Git");
-    const dialog = await screen.findByRole("dialog", { name: "Git" });
-    fireEvent.click(within(dialog).getByRole("button", { name: "dock Git left" }));
+    pickPlacement("Git", "Ancré à gauche");
     await screen.findByRole("complementary", { name: "left dock" });
 
-    // …then « Git → nouvelle fenêtre » pops it out.
-    openMenuItem("Window", "Git → nouvelle fenêtre");
+    // …then « Panneaux → Git → Fenêtre détachée » pops it out.
+    pickPlacement("Git", "Fenêtre détachée");
 
     await waitFor(() =>
       expect(windowGateway.open.has(`git|${projectId}`)).toBe(true),
@@ -80,26 +84,29 @@ describe("ProjectsView detach to OS window (#23)", () => {
   it("re-toggles the placement out of detached when the OS window closes", async () => {
     const { windowGateway, projectId } = await renderWithProject();
 
-    openMenuItem("Window", "Git → nouvelle fenêtre");
+    pickPlacement("Git", "Fenêtre détachée");
     await waitFor(() =>
       expect(windowGateway.open.has(`git|${projectId}`)).toBe(true),
     );
 
-    // The « Window » item shows the active marker (●) while detached.
-    const openWindowMenu = () =>
-      fireEvent.click(screen.getByRole("button", { name: "Window" }));
-    const gitWindowItem = () =>
-      screen.getByRole("button", { name: "Git → nouvelle fenêtre" });
+    // The « Fenêtre détachée » submenu leaf shows the active marker (●) while
+    // detached. Re-navigate the submenu each time to read it.
+    const openGitSubmenu = () => {
+      fireEvent.click(screen.getByRole("button", { name: "Panneaux" }));
+      fireEvent.click(screen.getByRole("button", { name: "Git" }));
+    };
+    const detachedLeaf = () =>
+      screen.getByRole("button", { name: "Fenêtre détachée" });
 
-    openWindowMenu();
-    await waitFor(() => expect(gitWindowItem().textContent).toContain("●"));
-    openWindowMenu(); // close the dropdown
+    openGitSubmenu();
+    await waitFor(() => expect(detachedLeaf().textContent).toContain("●"));
+    fireEvent.click(screen.getByRole("button", { name: "Panneaux" })); // close
 
     // The backend reports the OS window closed ⇒ the slot leaves "detached".
     windowGateway.simulateOsClose("git", projectId);
-    openWindowMenu();
+    openGitSubmenu();
     await waitFor(() =>
-      expect(gitWindowItem().textContent).not.toContain("●"),
+      expect(detachedLeaf().textContent).not.toContain("●"),
     );
   });
 });
diff --git a/frontend/src/features/projects/ProjectsView.docking.test.tsx b/frontend/src/features/projects/ProjectsView.docking.test.tsx
index 839f1b1..de40a12 100644
--- a/frontend/src/features/projects/ProjectsView.docking.test.tsx
+++ b/frontend/src/features/projects/ProjectsView.docking.test.tsx
@@ -47,10 +47,15 @@ async function renderWithProject() {
   );
 }
 
-/** Opens a menu-bar dropdown item. */
-function openMenuItem(menu: string, item: string) {
-  fireEvent.click(screen.getByRole("button", { name: menu }));
-  fireEvent.click(screen.getByRole("button", { name: item }));
+/**
+ * Opens a panel floating via the single « Panneaux » menu (#26): menu → panel
+ * entry (opens its placement submenu) → « Flottant ». `panelTitle` is the
+ * panel's human title ("Git", "Agents", …).
+ */
+function openPanelFloating(panelTitle: string) {
+  fireEvent.click(screen.getByRole("button", { name: "Panneaux" }));
+  fireEvent.click(screen.getByRole("button", { name: panelTitle }));
+  fireEvent.click(screen.getByRole("button", { name: "Flottant" }));
 }
 
 describe("ProjectsView view docking (#22)", () => {
@@ -58,7 +63,7 @@ describe("ProjectsView view docking (#22)", () => {
     await renderWithProject();
 
     // View → Git opens a modal floating window (historical behaviour).
-    openMenuItem("View", "Git");
+    openPanelFloating("Git");
     const dialog = await screen.findByRole("dialog", { name: "Git" });
     expect(dialog).toBeTruthy();
 
@@ -78,7 +83,7 @@ describe("ProjectsView view docking (#22)", () => {
   it("keeps one slot per view: docking right moves it off the left dock", async () => {
     await renderWithProject();
 
-    openMenuItem("View", "Git");
+    openPanelFloating("Git");
     const dialog = await screen.findByRole("dialog", { name: "Git" });
     fireEvent.click(within(dialog).getByRole("button", { name: "dock Git left" }));
 
@@ -100,7 +105,7 @@ describe("ProjectsView view docking (#22)", () => {
     await renderWithProject();
 
     // Dock Git left.
-    openMenuItem("View", "Git");
+    openPanelFloating("Git");
     fireEvent.click(
       within(await screen.findByRole("dialog", { name: "Git" })).getByRole(
         "button",
@@ -108,7 +113,7 @@ describe("ProjectsView view docking (#22)", () => {
       ),
     );
     // Dock Agents right.
-    openMenuItem("View", "Agents");
+    openPanelFloating("Agents");
     fireEvent.click(
       within(await screen.findByRole("dialog", { name: "Agents" })).getByRole(
         "button",
diff --git a/frontend/src/features/projects/ProjectsView.ls7.test.tsx b/frontend/src/features/projects/ProjectsView.ls7.test.tsx
index e2ac38c..efed359 100644
--- a/frontend/src/features/projects/ProjectsView.ls7.test.tsx
+++ b/frontend/src/features/projects/ProjectsView.ls7.test.tsx
@@ -112,10 +112,14 @@ function renderView(project: MockProjectGateway) {
   );
 }
 
-/** Opens a menu-bar dropdown item (#16 chrome). */
-function openMenuItem(menu: string, item: string) {
-  fireEvent.click(screen.getByRole("button", { name: menu }));
-  fireEvent.click(screen.getByRole("button", { name: item }));
+/**
+ * Opens a panel floating via the single « Panneaux » menu (#26): menu → panel
+ * entry (opens its placement submenu) → « Flottant ».
+ */
+function openPanel(panelTitle: string) {
+  fireEvent.click(screen.getByRole("button", { name: "Panneaux" }));
+  fireEvent.click(screen.getByRole("button", { name: panelTitle }));
+  fireEvent.click(screen.getByRole("button", { name: "Flottant" }));
 }
 
 async function openProjectAndWorkTab(label: string) {
@@ -127,7 +131,7 @@ async function openProjectAndWorkTab(label: string) {
   fireEvent.click(within(li!).getByRole("button", { name: "Open" }));
   await screen.findByRole("tab");
   // Open the Work panel window from the View menu.
-  openMenuItem("View", "Work");
+  openPanel("Work state");
 }
 
 describe("ProjectsView — LS7 conversation viewer integration", () => {
@@ -177,7 +181,7 @@ describe("ProjectsView — LS7 conversation viewer integration", () => {
     // persists across activation (the inline welcome list is replaced by the
     // grid once a project is active).
     await screen.findByText("/p/a");
-    openMenuItem("File", "Projects…");
+    openPanel("Projects");
     for (const root of ["/p/a", "/p/b"]) {
       const li = screen
         .getAllByRole("listitem")
@@ -188,7 +192,7 @@ describe("ProjectsView — LS7 conversation viewer integration", () => {
 
     // Make alpha the active tab, then open its conversation viewer.
     fireEvent.click(screen.getByRole("tab", { name: "alpha" }));
-    openMenuItem("View", "Work");
+    openPanel("Work state");
     fireEvent.click(
       await screen.findByRole("button", { name: `open conversation ${CONV_ID}` }),
     );
diff --git a/frontend/src/features/projects/ProjectsView.tsx b/frontend/src/features/projects/ProjectsView.tsx
index 487faa7..0cb247e 100644
--- a/frontend/src/features/projects/ProjectsView.tsx
+++ b/frontend/src/features/projects/ProjectsView.tsx
@@ -4,20 +4,22 @@
  * IDE layout (full remaining height), reworked in ticket #16:
  *
  *   ┌───────────────────────────────────────────────────────┐
- *   │ PROJECT TABS  [ alpha × ][ beta × ]                   │
+ *   │ PROJECT TABS  [ alpha × ][ beta × ]              [ + ] │
  *   ├───────────────────────────────────────────────────────┤
- *   │ MENU BAR   File │ View                                │
+ *   │ MENU BAR   Panneaux │ Settings                        │
  *   ├───────────────────────────────────────────────────────┤
  *   │  MAIN — LayoutGrid (fills the FULL width)             │
  *   │  — or the projects manager / welcome when no project  │
  *   └───────────────────────────────────────────────────────┘
  *
  * The former left sidebar is gone: every panel (context, work, tickets, agents,
- * templates, skills, permissions, memory, git) is now reached from the **View**
- * menu and shown in a chrome-level {@link FloatingWindow}, freeing the main area
- * for the terminal grid. Project creation/opening lives under the **File** menu
- * and, when no project is open, inline in the welcome area (so it is always
- * reachable without a menu).
+ * templates, skills, permissions, memory, git, projects) is reached from the
+ * single **Panneaux** menu (#26), whose per-panel submenu picks the placement
+ * directly — closed / floating / docked left/right / detached OS window — and
+ * shows it in a chrome-level {@link FloatingWindow} or {@link DockRegion}.
+ * Project creation/switching is the **Projects** panel, opened by the tab-bar
+ * "+" (or `Panneaux → Projects`) and, when no project is open, shown inline in
+ * the welcome area (so it is always reachable).
  *
  * Pure presentation: all behaviour comes from {@link useProjects}. Styling via
  * `@/shared`; no inline styles beyond z-index tokens, no `invoke()`.
@@ -41,13 +43,14 @@ import {
   Input,
   MenuBar,
   Panel,
-  Tabs,
   zIndex,
   type FloatingWindowSize,
+  type MenuBarItem,
   type MenuBarMenu,
 } from "@/shared";
 import { useGateways } from "@/app/di";
 import { useProjects } from "./useProjects";
+import { ProjectTabs } from "./ProjectTabs";
 import { ViewPanelBody, type ViewPanelId } from "./ViewPanelBody";
 import {
   PANEL_TITLE,
@@ -206,14 +209,6 @@ export function ProjectsView() {
       return next;
     });
   }
-  // Menu toggle: open floating when closed, otherwise close (whatever the slot).
-  function toggleFloating(panel: PanelId) {
-    if (placementOf(placements, panel) === "closed") {
-      setPlacement(panel, "floating");
-    } else {
-      closePanel(panel);
-    }
-  }
   // Dismiss every floating view (docked views stay put). Used when a full-main
   // surface takes over so a modal window doesn't obscure it.
   function dismissFloating() {
@@ -279,88 +274,77 @@ export function ProjectsView() {
     dismissFloating();
   }
 
-  // Switch the active project from the always-visible selector: activate its
-  // open tab if present, otherwise open it (adds a tab). Leaving Settings so the
-  // project surface is shown.
-  function selectProject(projectId: string) {
-    setShowSettings(false);
-    if (vm.openTabs.some((t) => t.id === projectId)) {
-      vm.activateTab(projectId);
-    } else {
-      void vm.openProject(projectId);
+  // ── Menus (#26) ─────────────────────────────────────────────────────────
+  // A single « Panneaux » menu: one entry per panel, each opening a submenu with
+  // the placement actions directly (closed / floating / docked left/right /
+  // detached OS window). One place to pick the panel *and* its mode; the current
+  // placement is marked in the submenu (and the parent entry shows ● when the
+  // panel is open somewhere). Order per UX: content panels first, Projects last.
+  const panelOrder: PanelId[] = [
+    "context",
+    "work",
+    "tickets",
+    "agents",
+    "templates",
+    "skills",
+    "permissions",
+    "memory",
+    "git",
+    "projects",
+  ];
+
+  // Placement actions for one panel, marking the active slot. `projects` is
+  // main-window-only chrome, so it never offers the detached-window action.
+  function placementSubmenu(panel: PanelId): MenuBarItem[] {
+    const placement = placementOf(placements, panel);
+    const items: MenuBarItem[] = [
+      {
+        id: "closed",
+        label: "Fermé",
+        active: placement === "closed",
+        onSelect: () => closePanel(panel),
+      },
+      {
+        id: "floating",
+        label: "Flottant",
+        active: placement === "floating",
+        onSelect: () => setPlacement(panel, "floating"),
+      },
+      {
+        id: "dock-left",
+        label: "Ancré à gauche",
+        active: isDockedTo(placement, "left"),
+        onSelect: () => setPlacement(panel, { dock: "left" }),
+      },
+      {
+        id: "dock-right",
+        label: "Ancré à droite",
+        active: isDockedTo(placement, "right"),
+        onSelect: () => setPlacement(panel, { dock: "right" }),
+      },
+    ];
+    if (panel !== "projects") {
+      items.push({
+        id: "detached",
+        label: "Fenêtre détachée",
+        active: isDetached(placement),
+        disabled: !active,
+        onSelect: () => detachPanel(panel),
+      });
     }
+    return items;
   }
 
-  // ── Menus ──────────────────────────────────────────────────────────────
-  const viewItems: { id: PanelId; label: string }[] = [
-    { id: "context", label: "Context" },
-    { id: "work", label: "Work" },
-    { id: "tickets", label: "Tickets" },
-    { id: "agents", label: "Agents" },
-    { id: "templates", label: "Templates" },
-    { id: "skills", label: "Skills" },
-    { id: "permissions", label: "Perms" },
-    { id: "memory", label: "Memory" },
-    { id: "git", label: "Git" },
-  ];
-  // Always-visible project selector (left of the menus): shows the active
-  // project and lists every known project so the user can switch without opening
-  // the Projects window (#16 UX pass).
-  const projectMenu: MenuBarMenu = {
-    id: "project",
-    label: `Projet : ${active?.name ?? "—"}`,
-    items:
-      vm.projects.length === 0
-        ? [
-            {
-              id: "none",
-              label: "No projects yet",
-              disabled: true,
-              onSelect: () => {},
-            },
-          ]
-        : vm.projects.map((p) => ({
-            id: p.id,
-            label: p.name,
-            active: p.id === active?.id,
-            onSelect: () => selectProject(p.id),
-          })),
-  };
   const menus: MenuBarMenu[] = [
-    projectMenu,
     {
-      id: "file",
-      label: "File",
-      items: [
-        {
-          id: "projects",
-          label: "Projects…",
-          active: placementOf(placements, "projects") !== "closed",
-          onSelect: () => toggleFloating("projects"),
-        },
-      ],
-    },
-    {
-      id: "view",
-      label: "View",
-      items: viewItems.map((it) => ({
-        id: it.id,
-        label: it.label,
-        active: placementOf(placements, it.id) !== "closed",
-        onSelect: () => toggleFloating(it.id),
-      })),
-    },
-    {
-      // #23: pop a view out into its own OS window. Disabled without an active
-      // project (the detached window is project-scoped); active ⇒ detached.
-      id: "window",
-      label: "Window",
-      items: viewItems.map((it) => ({
-        id: it.id,
-        label: `${PANEL_TITLE[it.id]} → nouvelle fenêtre`,
-        active: isDetached(placementOf(placements, it.id)),
-        disabled: !active,
-        onSelect: () => detachPanel(it.id),
+      id: "panels",
+      label: "Panneaux",
+      items: panelOrder.map((panel) => ({
+        id: panel,
+        label: PANEL_TITLE[panel],
+        active: placementOf(placements, panel) !== "closed",
+        onSelect: () => {},
+        submenu: placementSubmenu(panel),
       })),
     },
     {
@@ -575,20 +559,18 @@ export function ProjectsView() {
         </p>
       )}
 
-      {/* ── Project tab bar ── */}
-      <div className="flex shrink-0 items-center gap-1 border-b border-border bg-surface px-2 py-1">
-        {vm.openTabs.length === 0 ? (
-          <p className="px-2 text-sm text-muted">No open tabs.</p>
-        ) : (
-          <Tabs
-            items={vm.openTabs.map((t) => ({ id: t.id, label: t.name }))}
-            value={vm.activeTabId}
-            onSelect={(id) => vm.activateTab(id)}
-            onClose={(id) => void vm.closeTab(id)}
-            className="flex-1"
-          />
-        )}
-      </div>
+      {/* ── Project tab bar (#26): tabs = open projects, "+" opens Projects ── */}
+      <ProjectTabs
+        items={vm.openTabs.map((t) => ({ id: t.id, label: t.name }))}
+        activeTabId={vm.activeTabId}
+        onSelect={(id) => vm.activateTab(id)}
+        onClose={(id) => void vm.closeTab(id)}
+        projectsPanelOpen={placementOf(placements, "projects") !== "closed"}
+        onOpenProjectsPanel={() => {
+          setShowSettings(false);
+          setPlacement("projects", "floating");
+        }}
+      />
 
       {/* ── Menu bar (replaces the former left sidebar) ── */}
       <MenuBar menus={menus} />
diff --git a/frontend/src/features/projects/projects.test.tsx b/frontend/src/features/projects/projects.test.tsx
index 5fa700a..e30fbaa 100644
--- a/frontend/src/features/projects/projects.test.tsx
+++ b/frontend/src/features/projects/projects.test.tsx
@@ -75,11 +75,19 @@ function tablist() {
 }
 
 /**
- * Opens a menu-bar dropdown item (#16 chrome). `menu` is a top-level menu
- * ("File"/"View"), `item` a panel entry ("Work", "Agents", "Projects…", …).
- * The panel then shows in its floating window.
+ * Opens a panel floating via the single « Panneaux » menu (#26): click the menu,
+ * click the panel entry (opens its placement submenu), then pick « Flottant ».
+ * `panelTitle` is the panel's human title ("Work state", "Project context",
+ * "Agents", "Git", "Projects", …).
  */
-function openPanel(menu: string, item: string) {
+function openPanel(panelTitle: string) {
+  fireEvent.click(screen.getByRole("button", { name: "Panneaux" }));
+  fireEvent.click(screen.getByRole("button", { name: panelTitle }));
+  fireEvent.click(screen.getByRole("button", { name: "Flottant" }));
+}
+
+/** Clicks an item in a flat top-level menu (e.g. Settings). */
+function openMenuItem(menu: string, item: string) {
   fireEvent.click(screen.getByRole("button", { name: menu }));
   fireEvent.click(screen.getByRole("button", { name: item }));
 }
@@ -97,7 +105,7 @@ describe("ProjectsView (with MockProjectGateway)", () => {
     expect(tab.getAttribute("aria-selected")).toBe("true");
     expect(within(tab).getByText("alpha")).toBeTruthy();
     // And it is listed in the projects manager (File → Projects…) with its root.
-    openPanel("File", "Projects…");
+    openPanel("Projects");
     expect(
       (await screen.findAllByText("/home/me/alpha")).length,
     ).toBeGreaterThan(0);
@@ -116,7 +124,7 @@ describe("ProjectsView (with MockProjectGateway)", () => {
 
     // Open the projects manager window so the list persists across activation
     // (the inline welcome list is replaced by the terminal grid once active).
-    openPanel("File", "Projects…");
+    openPanel("Projects");
 
     // Open alpha, then beta — re-querying the list after each activation.
     const openInList = (name: string) =>
@@ -155,12 +163,12 @@ describe("ProjectsView (with MockProjectGateway)", () => {
     fireEvent.click(screen.getByRole("button", { name: "Open" }));
     await screen.findByRole("tab", { name: "alpha" });
 
-    openPanel("View", "Work");
+    openPanel("Work state");
 
     expect(await screen.findByText("No agent work state.")).toBeTruthy();
   });
 
-  it("switches the active project from the always-visible project selector (#16)", async () => {
+  it("switches the active project via the tab-bar + button → Projects panel (#26)", async () => {
     const project = new MockProjectGateway();
     await project.createProject("alpha", "/p/a");
     await project.createProject("beta", "/p/b");
@@ -174,17 +182,15 @@ describe("ProjectsView (with MockProjectGateway)", () => {
     fireEvent.click(within(alphaLi).getByRole("button", { name: "Open" }));
     await screen.findByRole("tab", { name: "alpha" });
 
-    // The selector reflects the active project and lists all known projects.
-    fireEvent.click(screen.getByRole("button", { name: "Projet : alpha" }));
-    // Pick beta from the selector — it opens/activates without the Projects window.
-    fireEvent.click(screen.getByRole("button", { name: "beta" }));
+    // The "+" button opens the Projects panel (floating); pick beta from its
+    // known-projects list — no verbose "Projet : …" selector anymore.
+    fireEvent.click(screen.getByRole("button", { name: "open projects panel" }));
+    const betaLi = await waitFor(() =>
+      screen.getAllByRole("listitem").find((n) => within(n).queryByText("beta"))!,
+    );
+    fireEvent.click(within(betaLi).getByRole("button", { name: "Open" }));
 
-    await waitFor(() =>
-      expect(screen.getByRole("button", { name: "Projet : beta" })).toBeTruthy(),
-    );
-    await waitFor(() =>
-      expect(screen.getAllByRole("tab")).toHaveLength(2),
-    );
+    await waitFor(() => expect(screen.getAllByRole("tab")).toHaveLength(2));
     const betaTab = screen
       .getAllByRole("tab")
       .find((t) => within(t).queryByText("beta"))!;
@@ -200,12 +206,12 @@ describe("ProjectsView (with MockProjectGateway)", () => {
     expect(screen.queryByLabelText("ai profiles settings")).toBeNull();
 
     // Settings → AI Profiles swaps the main area to the profiles settings.
-    openPanel("Settings", "AI Profiles");
+    openMenuItem("Settings", "AI Profiles");
     expect(await screen.findByLabelText("ai profiles settings")).toBeTruthy();
     expect(screen.queryByLabelText("project name")).toBeNull();
 
     // Settings → Close AI Profiles returns to the project surface.
-    openPanel("Settings", "Close AI Profiles");
+    openMenuItem("Settings", "Close AI Profiles");
     await waitFor(() =>
       expect(screen.getByLabelText("project name")).toBeTruthy(),
     );
@@ -233,7 +239,7 @@ describe("ProjectsView (with MockProjectGateway)", () => {
 
     // Reopen the projects manager (the inline form is replaced by the grid once
     // a project is active), then create a second project at the same root.
-    openPanel("File", "Projects…");
+    openPanel("Projects");
     await createProject("beta", "/dup/root");
 
     const alert = await screen.findByRole("alert");
@@ -255,40 +261,40 @@ describe("ProjectsView (with MockProjectGateway)", () => {
     );
 
     // File → Projects… opens the projects manager window — form inputs visible.
-    openPanel("File", "Projects…");
+    openPanel("Projects");
     await waitFor(() =>
       expect(screen.getByLabelText("project name")).toBeTruthy(),
     );
 
     // View → Agents — agent form visible; project form window is replaced.
-    openPanel("View", "Agents");
+    openPanel("Agents");
     await waitFor(() =>
       expect(screen.getByLabelText("agent name")).toBeTruthy(),
     );
     expect(screen.queryByLabelText("project name")).toBeNull();
 
     // View → Context — shared project context editor visible.
-    openPanel("View", "Context");
+    openPanel("Project context");
     await waitFor(() =>
       expect(screen.getByLabelText("project context")).toBeTruthy(),
     );
     expect(screen.queryByLabelText("agent name")).toBeNull();
 
     // View → Templates — the "New template" button visible.
-    openPanel("View", "Templates");
+    openPanel("Templates");
     await waitFor(() =>
       expect(screen.getByRole("button", { name: "create template" })).toBeTruthy(),
     );
     expect(screen.queryByLabelText("agent name")).toBeNull();
 
     // View → Git — commit message input visible.
-    openPanel("View", "Git");
+    openPanel("Git");
     await waitFor(() =>
       expect(screen.getByLabelText("commit message")).toBeTruthy(),
     );
 
     // File → Projects… again — form accessible once more.
-    openPanel("File", "Projects…");
+    openPanel("Projects");
     await waitFor(() =>
       expect(screen.getByLabelText("project name")).toBeTruthy(),
     );
@@ -302,7 +308,7 @@ describe("ProjectsView (with MockProjectGateway)", () => {
 
     await screen.findByText("/p/a");
     fireEvent.click(screen.getByRole("button", { name: "Open" }));
-    openPanel("View", "Context");
+    openPanel("Project context");
 
     const editor = (await screen.findByLabelText(
       "project context",
diff --git a/frontend/src/shared/ui/MenuBar.tsx b/frontend/src/shared/ui/MenuBar.tsx
index 10d5026..d33c5a8 100644
--- a/frontend/src/shared/ui/MenuBar.tsx
+++ b/frontend/src/shared/ui/MenuBar.tsx
@@ -23,6 +23,12 @@ export interface MenuBarItem {
   disabled?: boolean;
   /** Renders a selected/active marker (e.g. the currently-open panel). */
   active?: boolean;
+  /**
+   * Nested items shown in a side flyout (#26). When present, the item opens its
+   * submenu on hover/click instead of running `onSelect`; selecting a leaf item
+   * of the submenu runs that leaf's `onSelect` and closes the whole menu.
+   */
+  submenu?: MenuBarItem[];
 }
 
 export interface MenuBarMenu {
@@ -38,16 +44,24 @@ export interface MenuBarProps {
 
 export function MenuBar({ menus, className }: MenuBarProps) {
   const [openId, setOpenId] = useState<string | null>(null);
+  // Which item's submenu flyout is currently open (at most one, #26). Reset
+  // whenever the top-level menu changes or closes.
+  const [openSubId, setOpenSubId] = useState<string | null>(null);
   const rootRef = useRef<HTMLDivElement>(null);
 
+  function closeMenus() {
+    setOpenId(null);
+    setOpenSubId(null);
+  }
+
   // Close on outside click and on Escape while a menu is open.
   useEffect(() => {
     if (openId === null) return;
     function onPointerDown(e: MouseEvent) {
-      if (!rootRef.current?.contains(e.target as Node)) setOpenId(null);
+      if (!rootRef.current?.contains(e.target as Node)) closeMenus();
     }
     function onKeyDown(e: KeyboardEvent) {
-      if (e.key === "Escape") setOpenId(null);
+      if (e.key === "Escape") closeMenus();
     }
     document.addEventListener("mousedown", onPointerDown);
     document.addEventListener("keydown", onKeyDown);
@@ -73,7 +87,10 @@ export function MenuBar({ menus, className }: MenuBarProps) {
               type="button"
               aria-haspopup="menu"
               aria-expanded={open}
-              onClick={() => setOpenId((cur) => (cur === menu.id ? null : menu.id))}
+              onClick={() => {
+                setOpenSubId(null);
+                setOpenId((cur) => (cur === menu.id ? null : menu.id));
+              }}
               className={cn(
                 "rounded px-2.5 py-1 text-sm transition-colors",
                 open
@@ -93,29 +110,89 @@ export function MenuBar({ menus, className }: MenuBarProps) {
                   "bg-surface py-1 shadow-xl",
                 )}
               >
-                {menu.items.map((item) => (
-                  <button
-                    key={item.id}
-                    type="button"
-                    disabled={item.disabled}
-                    onClick={() => {
-                      item.onSelect();
-                      setOpenId(null);
-                    }}
-                    className={cn(
-                      "flex w-full items-center justify-between gap-3 px-3 py-1.5 text-left text-sm transition-colors",
-                      "text-content hover:bg-raised",
-                      "disabled:cursor-not-allowed disabled:opacity-50 disabled:hover:bg-transparent",
-                    )}
-                  >
-                    <span>{item.label}</span>
-                    {item.active && (
-                      <span aria-hidden className="text-primary">
-                        ●
-                      </span>
-                    )}
-                  </button>
-                ))}
+                {menu.items.map((item) => {
+                  const hasSub = (item.submenu?.length ?? 0) > 0;
+                  const subOpen = hasSub && openSubId === item.id;
+                  return (
+                    <div
+                      key={item.id}
+                      className="relative"
+                      onMouseEnter={() =>
+                        setOpenSubId(hasSub ? item.id : null)
+                      }
+                    >
+                      <button
+                        type="button"
+                        disabled={item.disabled}
+                        aria-haspopup={hasSub ? "menu" : undefined}
+                        aria-expanded={hasSub ? subOpen : undefined}
+                        onClick={() => {
+                          if (hasSub) {
+                            setOpenSubId((cur) =>
+                              cur === item.id ? null : item.id,
+                            );
+                            return;
+                          }
+                          item.onSelect();
+                          closeMenus();
+                        }}
+                        className={cn(
+                          "flex w-full items-center justify-between gap-3 px-3 py-1.5 text-left text-sm transition-colors",
+                          "text-content hover:bg-raised",
+                          "disabled:cursor-not-allowed disabled:opacity-50 disabled:hover:bg-transparent",
+                        )}
+                      >
+                        <span>{item.label}</span>
+                        {hasSub ? (
+                          <span aria-hidden className="text-muted">
+                            {item.active ? "● ▸" : "▸"}
+                          </span>
+                        ) : (
+                          item.active && (
+                            <span aria-hidden className="text-primary">
+                              ●
+                            </span>
+                          )
+                        )}
+                      </button>
+                      {subOpen && (
+                        <div
+                          role="menu"
+                          aria-label={item.label}
+                          style={{ zIndex: zIndex.floatingWindowNested }}
+                          className={cn(
+                            "absolute left-full top-0 ml-1 min-w-44 rounded-md border border-border",
+                            "bg-surface py-1 shadow-xl",
+                          )}
+                        >
+                          {item.submenu!.map((sub) => (
+                            <button
+                              key={sub.id}
+                              type="button"
+                              disabled={sub.disabled}
+                              onClick={() => {
+                                sub.onSelect();
+                                closeMenus();
+                              }}
+                              className={cn(
+                                "flex w-full items-center justify-between gap-3 px-3 py-1.5 text-left text-sm transition-colors",
+                                "text-content hover:bg-raised",
+                                "disabled:cursor-not-allowed disabled:opacity-50 disabled:hover:bg-transparent",
+                              )}
+                            >
+                              <span>{sub.label}</span>
+                              {sub.active && (
+                                <span aria-hidden className="text-primary">
+                                  ●
+                                </span>
+                              )}
+                            </button>
+                          ))}
+                        </div>
+                      )}
+                    </div>
+                  );
+                })}
               </div>
             )}
           </div>