diff --git a/Agent.md b/Agent.md
index 8297280..2c2e1d2 100644
--- a/Agent.md
+++ b/Agent.md
@@ -85,7 +85,7 @@ Usage: say "tool loop" for the whole process, "round N" for a single LLM request
   - 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` (236: 44 daemon_client + 19 conn-manager + 22 app-commands + 114 renderer smoke + 15 i18n + 7 integration + 3 commands + 5 build-config + 7 gui-state); RESPONSE_TYPES mirror daemon protocol verified against `daemon.py`
+  - Unit tests `npm test` (237: 44 daemon_client + 19 conn-manager + 22 app-commands + 115 renderer smoke + 15 i18n + 7 integration + 3 commands + 5 build-config + 7 gui-state); RESPONSE_TYPES mirror daemon protocol verified against `daemon.py`
 - **Scheduled tasks** — Task generalization + CRUD (rant 2026-08-12T18:23:15, #709/#710/#711)
   - Task handler generalized: `TaskHandler` (renamed from `EvolutionHandler`), repo-configured self-heal for any project, template lookup builtin → `~/.emrg/task-templates/<name>.md` → fallback
   - Daemon commands: `task_create/update/delete` + `task_template_create/list/update/delete` (tasks stored in `~/.emrg/tasks.yml`, custom type templates in `~/.emrg/task-templates/`)
@@ -119,7 +119,7 @@ pkill -f "emrg.server"; rm -f ~/.emrg/emrgd.port; python -m emrg
 ```
 
 Python: `uv run pytest tests/ -v` (801) — import check: `uv run python -c "from emrg.client.app import run_client"`
-GUI: `cd emrg/gui && npm test` (236: 44 daemon_client + 19 conn-manager + 22 app-commands + 114 renderer smoke + 15 i18n + 7 integration + 3 commands + 5 build-config + 7 gui-state) — syntax: `node --check main.js preload.js daemon_client.js renderer/js/*.js`
+GUI: `cd emrg/gui && npm test` (237: 44 daemon_client + 19 conn-manager + 22 app-commands + 115 renderer smoke + 15 i18n + 7 integration + 3 commands + 5 build-config + 7 gui-state) — syntax: `node --check main.js preload.js daemon_client.js renderer/js/*.js`
 CI: `uv run pytest` (ubuntu + **windows-2025 matrix** — Windows pytest 回归在 PR CI 即失败，v0.2.29 教训 #725) + 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/emrg/gui/renderer/js/app.js b/emrg/gui/renderer/js/app.js
index 6e6cdcf..a467c4a 100644
--- a/emrg/gui/renderer/js/app.js
+++ b/emrg/gui/renderer/js/app.js
@@ -567,13 +567,16 @@ const App = (() => {
       const panel = $(`panel-${p}`);
       if (panel) panel.classList.remove("active");
     }
+    // 浏览器 tab 语义：仅**新建**容器滚到底；既有容器保留滚动位置（rant 18:55:09 验收
+    // "回会话视图滚动位置保留"——面板往返/会话切换不跳底）
+    const existed = [...$("workspace").children].some((c) => c.dataset?.sid === sid);
     const view = ensureSessionView(sid);
     for (const child of $("workspace").children) {
       if (child.classList) child.classList.remove("active");
     }
     view.classList.add("active");
-    Chat.scrollToBottom(sid);
-    setWorkspaceChrome("sessions"); // 恢复输入区 + 成果面板
+    if (!existed) Chat.scrollToBottom(sid);
+    setWorkspaceChrome("sessions"); // 恢复输入区 + 成果面板（含 back-to-bottom 按位置恢复）
     state.activeView = "sessions";
     return view;
   }
@@ -694,21 +697,45 @@ const App = (() => {
     const empty = $("empty-state");
     const panel = $("result-panel");
     const resizer = $("result-resizer");
+    const btb = $("back-to-bottom");
     if (mode === "panel") {
       composer.classList.add("hidden");
       empty.classList.add("hidden");
       if (panel) panel.classList.add("hidden");
       if (resizer) resizer.classList.add("hidden");
+      if (btb) btb.classList.add("hidden"); // 回到底部按钮属会话视图，面板视图下隐藏
       // HTML 预览（WebContentsView）随面板隐藏（main 侧比对路径；无预览时 no-op）
       try { if (window.emrg && typeof window.emrg.closePreview === "function") window.emrg.closePreview({}); } catch { /* ignore */ }
     } else {
       composer.classList.remove("hidden");
       if (panel) panel.classList.remove("hidden");
       if (resizer) resizer.classList.remove("hidden");
+      updateBackToBottomState(); // 回会话视图：按当前滚动位置恢复按钮
       updateEmptyState();
     }
   }
 
+  /** 当前滚动容器：激活会话的 .session-view（#workspace overflow:hidden 自身不滚动） */
+  function activeScrollEl() {
+    const ws = $("workspace");
+    if (state.sessionId) {
+      const v = [...(ws.children || [])].find((c) => c.dataset?.sid === state.sessionId);
+      if (v) return v;
+    }
+    const active = [...(ws.children || [])].find((c) => c.classList && c.classList.contains("active"));
+    return active || ws;
+  }
+
+  /** 更新"回到底部"按钮 + autoScroll（scroll 事件不冒泡 → 需 capture 捕获子 .session-view 滚动） */
+  function updateBackToBottomState() {
+    const btn = $("back-to-bottom");
+    const el = activeScrollEl();
+    const atBottom = el.scrollTop + el.clientHeight >= el.scrollHeight - 40;
+    state.autoScroll = atBottom;
+    // 上滑阅读（不在底部）→ 显示"回到底部"悬浮按钮（不打扰）
+    if (btn) btn.classList.toggle("hidden", atBottom);
+  }
+
   /** rant 14:10:14 P2：设置面板 tab 切换（模型服务/工作目录/GitHub/外观/语言/关于）。 */
   const SETTINGS_TABS = ["model", "workdir", "github", "appearance", "language", "about"];
   function switchSettingsTab(name) {
@@ -1638,16 +1665,12 @@ const App = (() => {
     });
 
     const chatView = $("workspace");
-    const updateBackToBottom = () => {
-      const btn = $("back-to-bottom");
-      const atBottom = chatView.scrollTop + chatView.clientHeight >= chatView.scrollHeight - 40;
-      state.autoScroll = atBottom;
-      // 上滑阅读（不在底部）→ 显示"回到底部"悬浮按钮（不打扰）
-      if (btn) btn.classList.toggle("hidden", atBottom);
-    };
-    chatView.addEventListener("scroll", updateBackToBottom);
+    // scroll 事件不冒泡 → 必须用 capture 捕获子 .session-view 的滚动（#634 起滚动容器下移；
+    // 此前监听挂在 #workspace 上从不触发，back-to-bottom 与滚动加载历史在真实 GUI 静默失效）
+    chatView.addEventListener("scroll", updateBackToBottomState, true);
     $("back-to-bottom").addEventListener("click", () => {
-      chatView.scrollTop = chatView.scrollHeight;
+      const el = activeScrollEl();
+      el.scrollTop = el.scrollHeight;
       state.autoScroll = true;
       $("back-to-bottom").classList.add("hidden");
     });
@@ -1661,7 +1684,7 @@ const App = (() => {
         clearTimeout(historyScrollTimer);
         historyScrollTimer = setTimeout(() => loadOlderHistory(state.sessionId), 150);
       }
-    }, { passive: true });
+    }, { capture: true, passive: true });
 
     // 空状态示例问题卡片 → 填入输入框
     $("empty-state").addEventListener("click", (e) => {
diff --git a/emrg/gui/test/renderer.smoke.test.js b/emrg/gui/test/renderer.smoke.test.js
index 0e21c4c..ebe60c3 100644
--- a/emrg/gui/test/renderer.smoke.test.js
+++ b/emrg/gui/test/renderer.smoke.test.js
@@ -2679,6 +2679,54 @@ test("rant 14:15:12：切会话加载最近历史（只读气泡 + 加载条）
   assert.ok(noMore, "无更多历史时加载条仍在（显示没有更多）");
 });
 
+test("rant 18:55:09 v0.2 回归：back-to-bottom 跟随会话视图滚动（scroll 不冒泡 → capture 捕获子 .session-view）", async () => {
+  const { ctx, els } = makeSandbox({
+    init: async () => ({
+      config_exists: true,
+      api_key_configured: true,
+      project_dir: "/tmp",
+      project_dir_valid: true,
+      server_id: "srv-1",
+      model: "m",
+      evolution_count: 0,
+      sessions: [{ session_id: "s1", title: "测试对话", updated_at: "2026-08-05T10:00:00Z" }],
+      open_sessions: [],
+      active_sid: "s1",
+    }),
+    switchSession: async () => ({}),
+  });
+  await vm.runInContext("App.boot()", ctx);
+  await tick();
+  const view = vm.runInContext('document.getElementById("workspace").querySelector(".session-view")', ctx);
+  const btn = els["back-to-bottom"];
+  // 初始：在底部 → 按钮隐藏、autoScroll=true
+  view.scrollTop = 100;
+  view.scrollHeight = 1000;
+  view.clientHeight = 100; // 100+100 >= 960? no → 不在底部
+  els["workspace"].dispatch("scroll", { target: view });
+  await tick();
+  assert.strictEqual(btn.classList.contains("hidden"), false, "上滑（不在底部）→ back-to-bottom 显示");
+  assert.strictEqual(vm.runInContext("App.state.autoScroll", ctx), false, "上滑 → autoScroll=false");
+  // 点按钮 → 回到底部：scrollTop=scrollHeight、按钮隐藏
+  vm.runInContext('document.getElementById("back-to-bottom").click()', ctx);
+  await tick();
+  assert.strictEqual(view.scrollTop, view.scrollHeight, "点击后滚动容器回到底部");
+  assert.strictEqual(btn.classList.contains("hidden"), true, "回到底部后按钮隐藏");
+  assert.strictEqual(vm.runInContext("App.state.autoScroll", ctx), true, "回到底部后 autoScroll=true");
+  // 面板视图激活 → 按钮强制隐藏（不悬浮覆盖面板）
+  view.scrollTop = 0;
+  els["workspace"].dispatch("scroll", { target: view });
+  await tick();
+  assert.strictEqual(btn.classList.contains("hidden"), false, "再次上滑 → 按钮复现");
+  await vm.runInContext('document.getElementById("nav-projects").click()', ctx);
+  await tick();
+  assert.strictEqual(btn.classList.contains("hidden"), true, "面板视图下 back-to-bottom 隐藏");
+  // 回会话视图 → 按钮按滚动位置恢复（仍在上滑位置 → 复现）
+  await vm.runInContext('document.getElementById("nav-projects").click()', ctx);
+  await tick();
+  assert.strictEqual(btn.classList.contains("hidden"), false, "回会话视图后按位置恢复按钮");
+});
+
 test("rant 18:55:09 v0.2：导航点击 → 工作区视图切换（面板整块显示 + 互斥 + 点同项关闭回会话）", async () => {
   const { ctx } = makeSandbox({
     init: async () => ({