diff --git a/Agent.md b/Agent.md
index ea9ce0be..493ee933 100644
--- a/Agent.md
+++ b/Agent.md
@@ -66,7 +66,7 @@ EMRG is a self-evolving AI agent architecture experiment. Python implementation,
   - Streaming chat with delta rendering (16ms batching), markdown on done (marked + DOMPurify + local highlight.js subset), tool call status cards (2000-char truncation + expand)
   - Session list/switch/new/delete + right-click rename (context menu, #423) synced with daemon; own-stream busy lock (G65); broadcast streams from other clients tagged "来自其他客户端"
   - Disconnect/reconnect: red status dot, auto daemon respawn (stale-port detection), session resume, input bar restored on disconnect (no 30s fake-timeout)
-  - Unit tests `npm test` (150: 43 daemon_client + 17 conn-manager + 22 app-commands + 40 renderer smoke + 15 i18n + 7 integration + 3 commands + 3 build-config); RESPONSE_TYPES mirror daemon protocol verified against `daemon.py`
+  - Unit tests `npm test` (153: 43 daemon_client + 17 conn-manager + 22 app-commands + 43 renderer smoke + 15 i18n + 7 integration + 3 commands + 3 build-config); RESPONSE_TYPES mirror daemon protocol verified against `daemon.py`
 - **Auto project tracking** — Automatically detects and records working directories; project-scoped sessions
 - **Rant-driven evolution** — User feedback via `/rant` drives automatic self-improvement cycles
 - **Headless GitHub auth** — Non-interactive evolution auto-extracts `GH_TOKEN` from git credential store (osxkeychain / credential helper); PR comment/LGTM queries fall back to REST API (GraphQL needs `read:org` scope)
@@ -94,7 +94,7 @@ pkill -f "emrg.server"; rm -f ~/.emrg/emrgd.port; python -m emrg
 ```
 
 Python: `uv run pytest tests/ -v` (680) — import check: `uv run python -c "from emrg.client.app import run_client"`
-GUI: `cd emrg/gui && npm test` (150: 43 daemon_client + 17 conn-manager + 22 app-commands + 40 renderer smoke + 15 i18n + 7 integration + 3 commands + 3 build-config) — syntax: `node --check main.js preload.js daemon_client.js renderer/js/*.js`
+GUI: `cd emrg/gui && npm test` (153: 43 daemon_client + 17 conn-manager + 22 app-commands + 43 renderer smoke + 15 i18n + 7 integration + 3 commands + 3 build-config) — syntax: `node --check main.js preload.js daemon_client.js renderer/js/*.js`
 CI: `uv run pytest` + GUI tests + **actionlint workflow lint** (`rhysd/actionlint@v1.7.12` gate, #444 — workflow 解析错误在 PR CI 即失败，如 `if:` secrets 上下文)
 Re-trigger: `scripts/re-trigger-ci.sh [branch]` (workflow_dispatch, #527 — 替代空 commit 重触发：Actions outage 会整段丢弃 push 事件，dispatch 走 API 路径不受影响)
 
diff --git a/README.cn.md b/README.cn.md
index cc900a4c..8a9fc2b9 100644
--- a/README.cn.md
+++ b/README.cn.md
@@ -282,7 +282,7 @@ uv run python -m emrg     # 启动 TUI
 cd emrg/gui
 npm ci               # 安装依赖（生产模式可 --omit=dev）
 npm start            # 启动 GUI（自动拉起 daemon）
-npm test             # 运行 Node 测试（150 项：43 daemon_client + 17 conn-manager + 22 app-commands + 40 renderer smoke + 15 i18n + 7 integration + 3 commands + 3 build-config；集成测试在 CI 跑，本地可 npm run test:integration）
+npm test             # 运行 Node 测试（153 项：43 daemon_client + 17 conn-manager + 22 app-commands + 43 renderer smoke + 15 i18n + 7 integration + 3 commands + 3 build-config；集成测试在 CI 跑，本地可 npm run test:integration）
 ```
 
 CI 通过 GitHub Actions 自动运行测试并检查冲突标记（`.github/workflows/test.yml`）。
diff --git a/README.md b/README.md
index fdcfeb54..babce42d 100644
--- a/README.md
+++ b/README.md
@@ -281,7 +281,7 @@ uv run python -m emrg     # launch TUI
 cd emrg/gui
 npm ci               # install deps (production: --omit=dev)
 npm start            # launch GUI (auto-starts daemon)
-npm test             # run Node tests (150: 43 daemon_client + 17 conn-manager + 22 app-commands + 40 renderer smoke + 15 i18n + 7 integration + 3 commands + 3 build-config; integration runs in CI, local: npm run test:integration)
+npm test             # run Node tests (153: 43 daemon_client + 17 conn-manager + 22 app-commands + 43 renderer smoke + 15 i18n + 7 integration + 3 commands + 3 build-config; integration runs in CI, local: npm run test:integration)
 ```
 
 CI runs tests and checks for conflict markers automatically via GitHub Actions (`.github/workflows/test.yml`).
diff --git a/emrg/gui/renderer/css/layout.css b/emrg/gui/renderer/css/layout.css
index 468f01f6..2c0ca395 100644
--- a/emrg/gui/renderer/css/layout.css
+++ b/emrg/gui/renderer/css/layout.css
@@ -112,17 +112,31 @@
   background: var(--bg);
 }
 
-/* 聊天滚动区：居中单栏最大 760px，左右留白 ≥24px */
+/* 聊天区包装（P3 slice 2：多会话容器——每会话一个 .session-view，display 切换） */
 #chat-view {
   flex: 1;
-  overflow-y: auto;
+  position: relative;
+  overflow: hidden;
   display: flex;
   flex-direction: column;
+}
+
+/* 每会话滚动容器：只有激活会话可见，切换 display 保留状态（浏览器 tab 效果） */
+.session-view {
+  position: absolute;
+  inset: 0;
+  overflow-y: auto;
+  display: none;
+  flex-direction: column;
   gap: var(--sp-5);
   padding: var(--sp-5) var(--sp-5) var(--sp-4);
   scroll-behavior: smooth;
 }
-#chat-view > * {
+.session-view.active {
+  display: flex;
+}
+#chat-view > *:not(.session-view),
+.session-view > * {
   width: 100%;
   max-width: 760px;
   margin-left: auto;
@@ -231,7 +245,8 @@ body.sidebar-collapsed #app {
   #sidebar {
     display: none;
   }
-  #chat-view {
+  /* #chat-view 现为绝对定位包装（padding 移入 .session-view，避免滚动条内缩） */
+  .session-view {
     padding: var(--sp-4) var(--sp-4) var(--sp-3);
   }
   #composer-wrap {
diff --git a/emrg/gui/renderer/js/app.js b/emrg/gui/renderer/js/app.js
index da55374c..ac0f172d 100644
--- a/emrg/gui/renderer/js/app.js
+++ b/emrg/gui/renderer/js/app.js
@@ -164,7 +164,7 @@ const App = (() => {
             return;
           }
           await window.emrg.clearSession({ sessionId: state.sessionId });
-          Chat.clear();
+          Chat.clear(state.sessionId);
           Chat.addSystemMessage(_t("app.cleared"));
           break;
         case "/compact":
@@ -323,7 +323,7 @@ const App = (() => {
   async function doRewind(recordIndex) {
     try {
       const res = await window.emrg.rewindSession({ sessionId: state.sessionId, recordIndex });
-      Chat.clear();
+      Chat.clear(state.sessionId);
       Chat.addSystemMessage(_t("app.rewound", { index: recordIndex, n: res.removedCount ?? 0 }));
     } catch (e) {
       Chat.addSystemMessage(_t("app.rewindFailed", { msg: e.message }));
@@ -553,6 +553,30 @@ const App = (() => {
   }
 
   // ── 会话 ─────────────────────────────────
+  // P3 slice 2：每会话一个 .session-view 容器（浏览器 tab 效果——切换 display 保留状态）
+  function ensureSessionView(sid) {
+    if (!sid) return $("chat-view");
+    // 在 wrapper 内按 dataset.sid 查找既有容器（不依赖 getElementById——测试沙箱对
+    // 未知 id 返回新 mock，且 mock 的 .id 不入 attributes；dataset 双端一致）
+    let view = [...$("chat-view").children].find((c) => c.dataset?.sid === sid);
+    if (!view) {
+      view = el("div", { class: "session-view", id: "chat-view-" + sid, dataset: { sid } });
+      $("chat-view").appendChild(view);
+    }
+    Chat.registerContainer(sid, view); // 幂等：重复注册覆盖同一元素
+    return view;
+  }
+
+  function activateSessionView(sid) {
+    const view = ensureSessionView(sid);
+    for (const child of $("chat-view").children) {
+      if (child.classList) child.classList.remove("active");
+    }
+    view.classList.add("active");
+    Chat.scrollToBottom(sid);
+    return view;
+  }
+
   async function switchSession(sid, opts = {}) {    // G65：busy 即自有流进行中/发送中（IPC 往返窗口内 ownStreamRequestId 尚未赋值）
     if (state.busy) {
       Chat.addSystemMessage(EMRG_Copy.COPY.sessionBusy);
@@ -562,8 +586,8 @@ const App = (() => {
       const res = await window.emrg.switchSession({ sessionId: sid });
       state.sessionId = sid;
       // P3 slice 1：切换只移动激活指针——每会话条目保留自己的 busy/ownStreamRequestId
-      // （G110 旧语义=清全局自有流标记；per-sid 后由各会话条目自己管理，P4 切回继续生成）
-      Chat.clear();
+      // P3 slice 2：激活该会话容器（状态保留，不 Chat.clear——切回继续看到原消息/流式现场）
+      activateSessionView(sid);
       updateEmptyState();
       if (res.error === "session_not_found") {
         Chat.addSystemMessage(_t("app.deletedSwitch"));
@@ -577,7 +601,7 @@ const App = (() => {
       }
       // G13：v1 不加载历史（G12）
       if (!opts.silent) {
-        Chat.addSystemMessage(_t("app.switched"));
+        Chat.addSystemMessage(_t("app.switched"), sid);
       }
       updateEmptyState();
       Sidebar.highlight(sid);
@@ -595,7 +619,8 @@ const App = (() => {
     try {
       const res = await window.emrg.newSession();
       state.sessionId = res.session_id;
-      Chat.clear();
+      activateSessionView(state.sessionId); // P3 slice 2：新会话独立容器（空）
+      Chat.clear(state.sessionId); // 新会话从空开始（容器可能被复用）
       updateEmptyState(); // 欢迎屏即反馈
       await refreshSessions();
       Sidebar.highlight(state.sessionId);
@@ -612,6 +637,10 @@ const App = (() => {
     }
     try {
       await window.emrg.deleteSession({ sessionId: sid });
+      // P3 slice 2：删除会话 → 释放其容器（若已打开）
+      Chat.unregisterContainer(sid);
+      const view = [...$("chat-view").children].find((c) => c.dataset?.sid === sid);
+      if (view) view.remove();
       if (state.sessionId === sid) {
         const remaining = state.sessions.filter((s) => s.session_id !== sid);
         if (remaining.length > 0) {
@@ -959,8 +988,9 @@ const App = (() => {
   // ── 空状态欢迎屏 ───────────────────────
   function updateEmptyState() {
     const empty = $("empty-state");
-    const chatView = $("chat-view");
-    empty.classList.toggle("hidden", chatView.children.length > 0);
+    // P3 slice 2：检查**激活会话**容器（wrapper 恒含 session-view 子节点，不能数 wrapper）
+    const activeView = Chat.chatContainer(state.sessionId);
+    empty.classList.toggle("hidden", activeView.children.length > 0);
   }
 
   // ── 输入条状态 ─────────────────────────
@@ -1297,6 +1327,7 @@ const App = (() => {
     switchSession,
     newSession,
     deleteSession,
+    activateSessionView, // P3 slice 2：激活会话容器（display 切换；导出供测试）
     refreshSessions,
     showConvMenu,
     handleEvent,
diff --git a/emrg/gui/renderer/js/chat.js b/emrg/gui/renderer/js/chat.js
index 4ca831e5..9f5cfb4b 100644
--- a/emrg/gui/renderer/js/chat.js
+++ b/emrg/gui/renderer/js/chat.js
@@ -20,9 +20,12 @@ const Chat = (() => {
     return sessionState.get(key);
   }
 
-  /** 该会话的渲染容器：已注册的独立容器优先，否则默认聊天区（P3 过渡期行为） */
+  /** 该会话的渲染容器：已注册的独立容器优先，其次当前激活会话的容器（无 sid 事件落激活会话，P3 slice 2），最后回退默认聊天区（单会话过渡期行为）。 */
   function chatContainer(sid) {
-    return containers.get(sid) || $("chat-view");
+    if (containers.has(sid)) return containers.get(sid);
+    const active = App.state?.sessionId;
+    if (active && containers.has(active)) return containers.get(active);
+    return $("chat-view");
   }
 
   /** P4 起：为新打开的会话注册独立容器；关闭时 unregister 清引用 */
diff --git a/emrg/gui/test/renderer.smoke.test.js b/emrg/gui/test/renderer.smoke.test.js
index 178b547a..7a1ca69d 100644
--- a/emrg/gui/test/renderer.smoke.test.js
+++ b/emrg/gui/test/renderer.smoke.test.js
@@ -36,7 +36,13 @@ function makeEl(id) {
     _update() { node.className = [...node._cls].join(" "); },
     className: "",
     textContent: "",
-    innerHTML: "",
+    _html: "",
+    get innerHTML() { return this._html; },
+    set innerHTML(v) {
+      this._html = v;
+      // 忠实 DOM：innerHTML = "" 清空子节点（Chat.clear 依赖；P3 s2 容器隔离判别）
+      if (v === "") { while (this.children.length) this.children[0].remove(); }
+    },
     value: "",
     disabled: false,
     title: "",
@@ -1060,3 +1066,70 @@ test("P3 s1: cancelled 带 sid → 只清该会话条目；无 sid → 清激活
   await vm.runInContext('App.handleEvent({ type: "cancelled", data: {} });', ctx);
   assert.strictEqual(ctx.App.state.busy, false, "no-sid cancelled clears active");
 });
+
+// ── P3 slice 2（rant 15:07:19）：每会话 .session-view 容器 + display 切换 ──
+
+test("P3 s2: activateSessionView 建独立容器并切换 display（仅激活可见）", async () => {
+  const { ctx, els } = makeSandbox({});
+  await tick();
+  await vm.runInContext(
+    'App.state.sessionId = "sess-a";' +
+    'App.activateSessionView("sess-a");' +
+    'App.state.sessionId = "sess-b";' +
+    'App.activateSessionView("sess-b");',
+    ctx
+  );
+  // 沙箱 getElementById 对未知 id 返回新 mock —— 视图经 Chat.chatContainer(sid) 取实际对象
+  const va = ctx.EMRG_Chat.chatContainer("sess-a");
+  const vb = ctx.EMRG_Chat.chatContainer("sess-b");
+  assert.notStrictEqual(va, vb, "two distinct per-session views");
+  assert.strictEqual(va.classList.contains("active"), false, "sess-a deactivated after switch");
+  assert.strictEqual(vb.classList.contains("active"), true, "sess-b is the active view");
+  assert.strictEqual(els["chat-view"].children.length, 2, "both views live under the #chat-view wrapper");
+  // 无 sid 渲染 → 落激活会话容器（slice 2 回退链第二跳）
+  ctx.EMRG_Chat.addSystemMessage("to-active");
+  assert.strictEqual(vb.children.length, 1, "unsid'd node goes to active session view");
+  assert.strictEqual(va.children.length, 0, "inactive view untouched (state preserved)");
+});
+
+test("P3 s2: Chat.clear 只清目标容器——无 sid 清激活，带 sid 定向清", async () => {
+  const { ctx } = makeSandbox({});
+  await tick();
+  await vm.runInContext(
+    'App.state.sessionId = "sess-a";' +
+    'App.activateSessionView("sess-a");' +
+    'App.state.sessionId = "sess-b";' +
+    'App.activateSessionView("sess-b");' +
+    'EMRG_Chat.addSystemMessage("msg-a", "sess-a");' +
+    'EMRG_Chat.addSystemMessage("msg-b", "sess-b");',
+    ctx
+  );
+  const va = ctx.EMRG_Chat.chatContainer("sess-a");
+  const vb = ctx.EMRG_Chat.chatContainer("sess-b");
+  assert.strictEqual(va.children.length, 1, "sess-a has its node");
+  assert.strictEqual(vb.children.length, 1, "sess-b has its node");
+  // 无 sid clear（/clear 的既有调用形态）→ 只清激活容器
+  ctx.EMRG_Chat.clear();
+  assert.strictEqual(vb.children.length, 0, "active view cleared");
+  assert.strictEqual(va.children.length, 1, "inactive view retained (切回继续看到原消息)");
+  // 带 sid clear → 定向清
+  ctx.EMRG_Chat.clear("sess-a");
+  assert.strictEqual(va.children.length, 0, "targeted clear empties sess-a");
+});
+
+test("P3 s2: 未注册 sid 的事件落激活容器，状态桶仍按 sid 隔离", async () => {
+  const { ctx } = makeSandbox({});
+  await tick();
+  await vm.runInContext(
+    'App.state.sessionId = "sess-x";' +
+    'App.activateSessionView("sess-x");',
+    ctx
+  );
+  const vx = ctx.EMRG_Chat.chatContainer("sess-x");
+  // 广播流（sid=sess-other 无独立容器，P4 前过渡）→ 节点落激活容器、状态入自己桶
+  ctx.EMRG_Chat.handleDelta([{ request_id: "r1", content: "fallback", done: false, delta: true }], "sess-other");
+  assert.strictEqual(vx.children.length, 1, "unregistered sid renders into active view");
+  assert.strictEqual(ctx.EMRG_Chat.groupNodesFor("sess-other").size, 1, "state bucket keyed by own sid");
+  assert.strictEqual(ctx.EMRG_Chat.groupNodesFor("sess-x").size, 0, "active bucket untouched by other sid");
+});
+