diff --git a/src/App.tsx b/src/App.tsx
index 63208cd..e919916 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -9,6 +9,7 @@ import { store, useStore } from './store'
 import { TaskSidebar } from './components/TaskSidebar'
 import { Conversation } from './components/Conversation'
 import { PreviewPane } from './components/PreviewPane'
+import { previewTabsKey } from './previewtabs'
 import { Workbench } from './components/Workbench'
 import { Workspaces, workspaceShortcuts } from './components/Workspaces'
 import { AgentTracker } from './components/AgentTracker'
@@ -30,10 +31,9 @@ export function App() {
   }, [])
 
   const ui = useStore(s => s.ui)
-  const previewOpen = useStore(s => {
-    const id = s.currentConvId
-    return id ? (s.previewTabs[id]?.length ?? 0) > 0 : false
-  })
+  // 预览键与 requestPreview 的落点一致（previewTabsKey）：空态（未选会话）点开
+  // 工件也要渲染预览区，否则点击只剩工件弹层关闭、毫无反馈。
+  const previewOpen = useStore(s => (s.previewTabs[previewTabsKey(s.currentConvId)]?.length ?? 0) > 0)
   const toast = useStore(s => s.toast)
   const trackerRunId = useStore(s => s.ui.trackerRunId)
   const previewExpanded = previewOpen && ui.previewExpanded
diff --git a/src/components/Conversation.tsx b/src/components/Conversation.tsx
index 568e464..fc13d81 100644
--- a/src/components/Conversation.tsx
+++ b/src/components/Conversation.tsx
@@ -124,7 +124,11 @@ function DeliverableCard({ artifact, updates = 0 }: { artifact: { artifactId: st
   const name = artifact.name || art?.name || '文件'
   const icon = artifactIcon(name, artifact.kind ?? art?.kind)
   const size = humanSize(art?.size)
-  const open = () => { if (art) store.requestPreview(art) }
+  const open = () => {
+    if (art) { store.requestPreview(art); return }
+    // 工件已不在当前项目（被删/跨项目残留）：给一句话反馈，不再无声无息。
+    store.toast(`「${name}」已不在当前项目中，无法预览`)
+  }
   return (
     <div className="deliverable-card mk-rise-in" data-artifact-chip={artifact.artifactId}>
       <button type="button" className="dc-open" title={`预览 ${name}`} onClick={open}>
diff --git a/src/components/PreviewPane.tsx b/src/components/PreviewPane.tsx
index fed98c7..75fec5e 100644
--- a/src/components/PreviewPane.tsx
+++ b/src/components/PreviewPane.tsx
@@ -5,12 +5,13 @@ import { Btn, FilePreview, Icon, TabStrip } from '@ui'
 import { api } from '../api'
 import type { Artifact } from '../contracts'
 import { humanSize } from '../messageparts'
+import { previewTabsKey } from '../previewtabs'
 import { store, useStore } from '../store'
 
 export function PreviewPane() {
-  const convId = useStore(s => s.currentConvId)
-  const tabs = useStore(s => (convId ? s.previewTabs[convId] : undefined) ?? [])
-  const activeId = useStore(s => (convId ? s.previewActive[convId] : null) ?? null)
+  // 键口径与 requestPreview 一致（previewTabsKey）：空态预览也渲染。
+  const tabs = useStore(s => s.previewTabs[previewTabsKey(s.currentConvId)] ?? [])
+  const activeId = useStore(s => s.previewActive[previewTabsKey(s.currentConvId)] ?? null)
   const artifacts = useStore(s => s.artifacts)
   const expanded = useStore(s => s.ui.previewExpanded)
   const active = tabs.find(t => t.id === activeId) ?? tabs[0]
diff --git a/src/previewtabs.ts b/src/previewtabs.ts
index 79ed08d..5875f3e 100644
--- a/src/previewtabs.ts
+++ b/src/previewtabs.ts
@@ -25,3 +25,23 @@ export function closePreviewTab(
   const neighbor = next[Math.min(i, next.length - 1)] ?? null
   return { tabs: next, activeId: neighbor?.id ?? null }
 }
+
+/** 预览标签的会话键。空态（未选会话）统一落在 '_'：写入（requestPreview）与
+ *  渲染（previewOpen/PreviewPane）共用同一口径，空态点开工件才能出现预览区。 */
+export function previewTabsKey(currentConvId: string | null | undefined): string {
+  return currentConvId ?? '_'
+}
+
+/** 进入会话时把空态打开的孤儿标签（'_' 键）并入会话键下；按 id 去重，
+ *  会话侧顺序在前，'_' 键清空。无孤儿或目标即 '_' 时原样返回。 */
+export function mergeOrphanPreviewTabs(
+  tabsByConv: Record<string, PreviewTab[]>,
+  convId: string,
+): Record<string, PreviewTab[]> {
+  const orphan = tabsByConv['_'] ?? []
+  if (orphan.length === 0 || convId === '_') return tabsByConv
+  const own = tabsByConv[convId] ?? []
+  const ids = new Set(own.map(t => t.id))
+  const merged = [...own, ...orphan.filter(t => !ids.has(t.id))]
+  return { ...tabsByConv, [convId]: merged, '_': [] }
+}
diff --git a/src/store.ts b/src/store.ts
index aab89a4..5eeabb2 100644
--- a/src/store.ts
+++ b/src/store.ts
@@ -3,7 +3,7 @@
 import { useSyncExternalStore } from 'react'
 import { api, connectEvents } from './api'
 import { applyTextDelta, applyThinkingDelta, applyToolCall, applyToolCallDelta, applyToolResult, applyToolOutput, applyArtifactCreated, applyArtifactUpdated, applyCheck, applyFinalizing, type LiveItem } from './live'
-import { closePreviewTab, openPreviewTab, type PreviewTab } from './previewtabs'
+import { closePreviewTab, mergeOrphanPreviewTabs, openPreviewTab, previewTabsKey, type PreviewTab } from './previewtabs'
 import { deliveryRequestId, enqueueMessage, enqueueMessageFront, newQueuedMessage, promoteQueuedMessage, removeQueuedMessage, replaceQueuedText, type QueuedMessage } from './outbox'
 import { canFlushOutbox, deriveShellPhase } from './runstate'
 import { flashElement } from './scrollsync'
@@ -184,6 +184,17 @@ function setUI(patch: Partial<UIState>) {
   listeners.forEach(l => l())
 }
 
+// 会话恢复（空态点工件无反应的高频前置）：currentConvId 不持久化时刷新必回空态，
+// 空态下 requestPreview 的标签挂在 '_' 键、渲染判空键——点击只剩弹层关闭，没有任何反馈。
+const CONV_KEY = 'as.conv'
+let convRestoreDone = false
+function persistConvId(id: string | null) {
+  try { id ? localStorage.setItem(CONV_KEY, id) : localStorage.removeItem(CONV_KEY) } catch { /* ignore */ }
+}
+function savedConvId(): string | null {
+  try { return localStorage.getItem(CONV_KEY) } catch { return null }
+}
+
 let systemQuery: MediaQueryList | null = null
 let systemHandler: (() => void) | null = null
 
@@ -252,7 +263,18 @@ export const store = {
 
   // 跨项目任务列表（方案 A 侧栏数据源）：归档视图切换时带 includeArchived 重取。
   async refreshTasks(includeArchived = state.ui.showArchived) {
-    try { set({ tasks: await api.listTasks(includeArchived) }) } catch { /* 列表竞态，静默 */ }
+    try {
+      const tasks = await api.listTasks(includeArchived)
+      set({ tasks })
+      // 首次加载恢复上次会话（仅一次；此后用户主动切换/新建不再打扰）。
+      if (!convRestoreDone) {
+        convRestoreDone = true
+        const saved = savedConvId()
+        if (saved && !state.currentConvId && tasks.some(t => t.id === saved && !t.archived)) {
+          store.openConversation(saved)
+        }
+      }
+    } catch { /* 列表竞态，静默 */ }
   },
 
   async refreshMe() {
@@ -336,6 +358,15 @@ export const store = {
   async openConversation(convId: string) {
     if (sse) { sse.close(); sse = null }
     set({ currentConvId: convId, messages: [], runs: [], activeHitl: [], lastSeq: 0, live: null, plan: null, todos: null, cards: [], inboxScope: 'conv', outbox: [], outboxDraining: false, posting: false })
+    persistConvId(convId)
+    // 空态时打开的预览标签（'_' 键）随会话进入一起迁移，不留在不可见的孤儿键下。
+    if ((state.previewTabs['_'] ?? []).length > 0) {
+      const active = state.previewActive[convId] ?? state.previewActive['_'] ?? null
+      set({
+        previewTabs: mergeOrphanPreviewTabs(state.previewTabs, convId),
+        previewActive: { ...state.previewActive, [convId]: active },
+      })
+    }
     syncPreviewRail((state.previewTabs[convId] ?? []).length > 0)
     const resumeSeq = await store.reconcile()
     store.connectLive(resumeSeq ?? state.lastSeq)
@@ -804,7 +835,7 @@ export const store = {
    * 打开第一张标签时收起右栏，关掉最后一张时恢复，并收回展开态。
    */
   requestPreview(a: Artifact) {
-    const conv = state.currentConvId ?? '_'
+    const conv = previewTabsKey(state.currentConvId)
     const opened = openPreviewTab(state.previewTabs[conv] ?? [], { id: a.id, name: a.name })
     set({
       previewTabs: { ...state.previewTabs, [conv]: opened.tabs },
@@ -814,11 +845,11 @@ export const store = {
   },
   togglePreviewExpanded() { setUI({ previewExpanded: !state.ui.previewExpanded }) },
   activatePreview(id: string) {
-    const conv = state.currentConvId ?? '_'
+    const conv = previewTabsKey(state.currentConvId)
     set({ previewActive: { ...state.previewActive, [conv]: id } })
   },
   closePreview(id: string) {
-    const conv = state.currentConvId ?? '_'
+    const conv = previewTabsKey(state.currentConvId)
     const next = closePreviewTab(state.previewTabs[conv] ?? [], state.previewActive[conv] ?? null, id)
     set({
       previewTabs: { ...state.previewTabs, [conv]: next.tabs },
diff --git a/test/preview-empty-state.test.ts b/test/preview-empty-state.test.ts
new file mode 100644
index 0000000..86a66b9
--- /dev/null
+++ b/test/preview-empty-state.test.ts
@@ -0,0 +1,30 @@
+// 空态点工件无反应（2026-10-10 实测复现）：requestPreview 写 '_' 键、渲染判
+// currentConvId 非空——键口径不一致导致空态点击只剩弹层关闭。这里测纯函数口径。
+import { describe, expect, it } from 'vitest'
+import { mergeOrphanPreviewTabs, previewTabsKey } from '../src/previewtabs'
+
+describe('previewTabsKey', () => {
+  it('falls back to the empty-state key when no conversation is selected', () => {
+    expect(previewTabsKey(null)).toBe('_')
+    expect(previewTabsKey(undefined)).toBe('_')
+    expect(previewTabsKey('cnv_1')).toBe('cnv_1')
+  })
+})
+
+describe('mergeOrphanPreviewTabs', () => {
+  it('merges empty-state tabs into the conversation key and clears the orphan key', () => {
+    const got = mergeOrphanPreviewTabs({
+      _: [{ id: 'a', name: 'A.docx' }, { id: 'b', name: 'B.md' }],
+      cnv_1: [{ id: 'b', name: 'B.md' }],
+    }, 'cnv_1')
+    expect(got._).toEqual([])
+    expect(got.cnv_1.map(t => t.id)).toEqual(['b', 'a'])
+  })
+
+  it('returns the input untouched when there is no orphan or the target is the orphan key', () => {
+    const none = { cnv_1: [{ id: 'a', name: 'A' }] }
+    expect(mergeOrphanPreviewTabs(none, 'cnv_1')).toBe(none)
+    const self = { _: [{ id: 'a', name: 'A' }] }
+    expect(mergeOrphanPreviewTabs(self, '_')).toBe(self)
+  })
+})