diff --git a/src/app/main/MainChatPanel.tsx b/src/app/main/MainChatPanel.tsx
index 9632072..72e36d3 100644
--- a/src/app/main/MainChatPanel.tsx
+++ b/src/app/main/MainChatPanel.tsx
@@ -5171,9 +5171,11 @@ export function MainChatPanel({
     activePreview,
     isPreviewLoading,
     isPreviewModalOpen,
+    previewModalTarget,
     previewContentType,
     previewError,
     previewText,
+    handlePreviewModalAfterOpenChange,
     setActivePreviewId,
     setActivePreviewOverride,
     setIsPreviewModalOpen,
@@ -9456,16 +9458,17 @@ export function MainChatPanel({
         </Space>
       </Modal>
       <FullscreenPreviewModal
-        open={isPreviewModalOpen && Boolean(activePreview)}
+        open={isPreviewModalOpen}
+        afterOpenChange={handlePreviewModalAfterOpenChange}
         title={
-          activePreview
-            ? `${activePreview.label} · ${activePreview.kind} · ${activePreview.source === 'context' ? '현재 화면' : '채팅 결과'}`
+          previewModalTarget
+            ? `${previewModalTarget.label} · ${previewModalTarget.kind} · ${previewModalTarget.source === 'context' ? '현재 화면' : '채팅 결과'}`
             : 'preview'
         }
         meta={null}
         actions={
           <>
-            {isActivePreviewHtml ? (
+            {previewModalTarget && isHtmlPreviewItem(previewModalTarget) ? (
               <>
                 <Button
                   type="text"
@@ -9487,7 +9490,7 @@ export function MainChatPanel({
                 />
               </>
             ) : null}
-            {canSearchActivePreview ? (
+            {previewModalTarget && canSearchActivePreview ? (
               <Button
                 type="text"
                 className="fullscreen-preview-modal__icon-button"
@@ -9526,7 +9529,7 @@ export function MainChatPanel({
         }}
         className={`app-chat-panel__preview-modal${isHtmlPreviewFullscreen ? ' app-chat-panel__preview-modal--html-mobile' : ''}`}
       >
-        {activePreview ? (
+        {previewModalTarget ? (
           <div className="app-chat-panel__preview-modal-body">
             {canSearchActivePreview && isPreviewFindOpen ? (
               <div className="app-chat-panel__preview-modal-findbar">
@@ -9570,7 +9573,7 @@ export function MainChatPanel({
               onPointerDownCapture={handlePreviewSearchRootPointerDown}
             >
               <ChatPreviewBody
-                target={activePreview}
+                target={previewModalTarget}
                 previewText={previewText}
                 isPreviewLoading={isPreviewLoading}
                 previewError={previewError}
diff --git a/src/app/main/chatV2/hooks/useConversationViewController.ts b/src/app/main/chatV2/hooks/useConversationViewController.ts
index c2b39d0..4ad6958 100644
--- a/src/app/main/chatV2/hooks/useConversationViewController.ts
+++ b/src/app/main/chatV2/hooks/useConversationViewController.ts
@@ -42,6 +42,7 @@ export function useConversationViewController({
   const [activePreviewId, setActivePreviewId] = useState<string | null>(null);
   const [activePreviewOverride, setActivePreviewOverride] = useState<PreviewItem | null>(null);
   const [isPreviewModalOpen, setIsPreviewModalOpen] = useState(false);
+  const [previewModalTarget, setPreviewModalTarget] = useState<PreviewItem | null>(null);
   const [previewText, setPreviewText] = useState('');
   const [isPreviewLoading, setIsPreviewLoading] = useState(false);
   const [previewError, setPreviewError] = useState('');
@@ -49,6 +50,14 @@ export function useConversationViewController({
 
   const activePreview = activePreviewOverride ?? previewItems.find((item) => item.id === activePreviewId) ?? previewItems[0] ?? null;
 
+  useEffect(() => {
+    if (!isPreviewModalOpen || !activePreview) {
+      return;
+    }
+
+    setPreviewModalTarget(activePreview);
+  }, [activePreview, isPreviewModalOpen]);
+
   useEffect(() => {
     const previousSessionId = previousSessionIdRef.current;
     const hasSessionChanged = previousSessionId !== activeSessionId;
@@ -98,7 +107,7 @@ export function useConversationViewController({
   }, [activePreviewId, activePreviewOverride, previewItems]);
 
   useEffect(() => {
-    if (!isPreviewModalOpen || !activePreview) {
+    if (!previewModalTarget) {
       setPreviewText('');
       setPreviewError('');
       setPreviewContentType('');
@@ -106,11 +115,15 @@ export function useConversationViewController({
       return;
     }
 
+    if (!isPreviewModalOpen) {
+      return;
+    }
+
     if (
-      activePreview.kind === 'image' ||
-      activePreview.kind === 'video' ||
-      activePreview.kind === 'pdf' ||
-      activePreview.kind === 'file'
+      previewModalTarget.kind === 'image' ||
+      previewModalTarget.kind === 'video' ||
+      previewModalTarget.kind === 'pdf' ||
+      previewModalTarget.kind === 'file'
     ) {
       setPreviewText('');
       setPreviewError('');
@@ -124,7 +137,7 @@ export function useConversationViewController({
     setPreviewError('');
     setPreviewContentType('');
 
-    fetch(activePreview.url, {
+    fetch(previewModalTarget.url, {
       cache: 'no-store',
       signal: controller.signal,
     })
@@ -155,7 +168,19 @@ export function useConversationViewController({
     return () => {
       controller.abort();
     };
-  }, [activePreview, isPreviewModalOpen]);
+  }, [isPreviewModalOpen, previewModalTarget]);
+
+  const handlePreviewModalAfterOpenChange = (open: boolean) => {
+    if (open) {
+      return;
+    }
+
+    setPreviewModalTarget(null);
+    setPreviewText('');
+    setPreviewError('');
+    setPreviewContentType('');
+    setIsPreviewLoading(false);
+  };
 
   useEffect(() => {
     const previousActiveView = previousActiveViewRef.current;
@@ -216,9 +241,11 @@ export function useConversationViewController({
     activePreviewId,
     isPreviewLoading,
     isPreviewModalOpen,
+    previewModalTarget,
     previewContentType,
     previewError,
     previewText,
+    handlePreviewModalAfterOpenChange,
     setActivePreviewId,
     setActivePreviewOverride,
     setIsPreviewModalOpen,
diff --git a/src/app/main/mainChatPanel/chatUtils.ts b/src/app/main/mainChatPanel/chatUtils.ts
index 8cad1e2..3f8b80c 100644
--- a/src/app/main/mainChatPanel/chatUtils.ts
+++ b/src/app/main/mainChatPanel/chatUtils.ts
@@ -1626,6 +1626,7 @@ async function requestChatApi<T>(
   init?: RequestInit,
   options?: {
     allowUnauthenticated?: boolean;
+    signal?: AbortSignal;
     timeoutMs?: number;
     sharePin?: string | null;
   },
@@ -1635,9 +1636,18 @@ async function requestChatApi<T>(
   const accessToken = getRegisteredAccessToken();
   const method = init?.method?.toUpperCase() ?? 'GET';
   const controller = new AbortController();
+  const externalAbortHandler = () => controller.abort();
   const timeoutMs = Number.isFinite(options?.timeoutMs) ? Math.max(1000, Number(options?.timeoutMs)) : 8000;
   const timeoutId = window.setTimeout(() => controller.abort(), timeoutMs);
 
+  if (options?.signal) {
+    if (options.signal.aborted) {
+      window.clearTimeout(timeoutId);
+      throw new DOMException('Aborted', 'AbortError');
+    }
+    options.signal.addEventListener('abort', externalAbortHandler, { once: true });
+  }
+
   if (!allowUnauthenticated && !hasRegisteredAccessTokenAccess()) {
     window.clearTimeout(timeoutId);
     throw new Error('등록된 접근 토큰이 없어 채팅 요청을 보낼 수 없습니다.');
@@ -1681,8 +1691,14 @@ async function requestChatApi<T>(
     });
   } catch (error) {
     window.clearTimeout(timeoutId);
+    if (options?.signal) {
+      options.signal.removeEventListener('abort', externalAbortHandler);
+    }
 
     if (error instanceof DOMException && error.name === 'AbortError') {
+      if (options?.signal?.aborted) {
+        throw error;
+      }
       throw new Error('채팅 서버 응답이 지연됩니다.');
     }
 
@@ -1690,6 +1706,9 @@ async function requestChatApi<T>(
   }
 
   window.clearTimeout(timeoutId);
+  if (options?.signal) {
+    options.signal.removeEventListener('abort', externalAbortHandler);
+  }
 
   if (!response.ok) {
     const contentType = response.headers.get('content-type')?.toLowerCase() ?? '';
@@ -2847,6 +2866,7 @@ export async function fetchChatShareSnapshot(
   options?: {
     sharePin?: string | null;
     sessionId?: string | null;
+    signal?: AbortSignal;
     view?: 'full' | 'initial';
   },
 ) {
@@ -2882,6 +2902,7 @@ export async function fetchChatShareSnapshot(
     undefined,
     {
       allowUnauthenticated: true,
+      signal: options?.signal,
       sharePin: options?.sharePin,
       timeoutMs: 20000,
     },
diff --git a/src/app/main/pages/ChatSharePage.tsx b/src/app/main/pages/ChatSharePage.tsx
index b43a612..d7528e4 100644
--- a/src/app/main/pages/ChatSharePage.tsx
+++ b/src/app/main/pages/ChatSharePage.tsx
@@ -1,7 +1,7 @@
 import { AppstoreOutlined, CheckOutlined, CloseOutlined, CommentOutlined, CopyOutlined, DeleteOutlined, DownOutlined, EditOutlined, EyeInvisibleOutlined, EyeOutlined, FileTextOutlined, FilterOutlined, FullscreenOutlined, LeftOutlined, MinusOutlined, PlusOutlined, ReloadOutlined, RightOutlined, SearchOutlined, SendOutlined, SettingOutlined, ThunderboltOutlined, UpOutlined } from '@ant-design/icons';
 import { Alert, App, Button, Checkbox, Drawer, Dropdown, Input, Modal, Select, Spin, Tabs, Tag, Typography, type MenuProps } from 'antd';
 import type { TextAreaRef } from 'antd/es/input/TextArea';
-import { Suspense, lazy, useCallback, useEffect, useLayoutEffect, useMemo, useRef, useState, type ClipboardEvent, type CSSProperties, type FocusEvent, type KeyboardEvent, type MouseEvent as ReactMouseEvent, type PointerEvent as ReactPointerEvent, type ReactNode } from 'react';
+import { Suspense, lazy, startTransition, useCallback, useEffect, useLayoutEffect, useMemo, useRef, useState, type ClipboardEvent, type CSSProperties, type FocusEvent, type KeyboardEvent, type MouseEvent as ReactMouseEvent, type PointerEvent as ReactPointerEvent, type ReactNode } from 'react';
 import { createPortal } from 'react-dom';
 import { useParams } from 'react-router-dom';
 import { FullscreenPreviewModal } from '../../../components/previewer';
@@ -110,6 +110,8 @@ const SHARE_LAST_ROOM_STORAGE_KEY = 'codex-live-share-last-room-by-token';
 const SHARE_ROOM_SNAPSHOT_SESSION_INDEX_STORAGE_KEY = 'codex-live-share-room-snapshot-index:v1';
 const SHARE_ROOM_SNAPSHOT_SESSION_STORAGE_KEY_PREFIX = 'codex-live-share-room-snapshot:v1';
 const SHARE_ROOM_SNAPSHOT_SESSION_CACHE_LIMIT = 6;
+const SHARE_ROOM_SWITCH_CACHE_REQUEST_LIMIT = 12;
+const SHARE_ROOM_SWITCH_CACHE_MESSAGE_LIMIT = 32;
 const SHARE_IMMEDIATE_SEND_TOGGLE_HOLD_MS = 1000;
 const SHARE_EDGE_NAVIGATION_HOTZONE_PX = 28;
 const SHARE_APPS_EDGE_MIDDLE_BAND_RATIO = 0.2;
@@ -140,6 +142,28 @@ type ShareMessageRenderPayload = ShareRenderedMessage & {
   previewItems: PreviewItem[];
 };
 
+type ShareRoomSwitchPerfStep = {
+  name: string;
+  at: number;
+  detailLevel?: ChatShareSnapshot['detailLevel'];
+  requestCount?: number;
+  messageCount?: number;
+  activityLogCount?: number;
+  hasCache?: boolean;
+};
+
+type ShareRoomSwitchPerfRun = {
+  id: string;
+  fromSessionId: string;
+  toSessionId: string;
+  startedAt: number;
+  steps: ShareRoomSwitchPerfStep[];
+};
+
+type ShareWindowWithPerf = Window & {
+  __chatShareRoomSwitchPerfRuns?: ShareRoomSwitchPerfRun[];
+};
+
 type ShareExpandMode = 'latest' | 'pending' | 'all';
 type PendingSharePromptSelection = PromptDraftSelection & {
   status: 'draft' | 'submitted';
@@ -593,7 +617,11 @@ function readStoredShareRoomSnapshot(token: string, sessionId: string) {
     }
 
     const cachedSessionId = resolveShareSnapshotCacheSessionId(snapshot);
-    return cachedSessionId === normalizedSessionId ? snapshot : null;
+    if (cachedSessionId !== normalizedSessionId) {
+      return null;
+    }
+
+    return buildShareRoomSwitchCacheSnapshot(snapshot);
   } catch {
     return null;
   }
@@ -643,9 +671,10 @@ function clearStoredShareRoomSnapshotCache(token: string) {
 
 function writeStoredShareRoomSnapshot(token: string, snapshot: ChatShareSnapshot | null | undefined) {
   const normalizedToken = token.trim();
-  const normalizedSessionId = resolveShareSnapshotCacheSessionId(snapshot);
+  const storedSnapshot = buildShareRoomSwitchCacheSnapshot(snapshot ?? null);
+  const normalizedSessionId = resolveShareSnapshotCacheSessionId(storedSnapshot);
 
-  if (!canUseShareRoomSnapshotSessionStorage() || !normalizedToken || !normalizedSessionId || !snapshot) {
+  if (!canUseShareRoomSnapshotSessionStorage() || !normalizedToken || !normalizedSessionId || !storedSnapshot) {
     return;
   }
 
@@ -656,7 +685,7 @@ function writeStoredShareRoomSnapshot(token: string, snapshot: ChatShareSnapshot
       buildShareRoomSnapshotSessionStorageKey(normalizedToken, normalizedSessionId),
       JSON.stringify({
         savedAt: nextSavedAt,
-        snapshot,
+        snapshot: storedSnapshot,
       }),
     );
     const nextIndex = readStoredShareRoomSnapshotSessionIndex();
@@ -681,6 +710,91 @@ function writeStoredShareRoomSnapshot(token: string, snapshot: ChatShareSnapshot
   }
 }
 
+function buildShareRoomSwitchCacheSnapshot(snapshot: ChatShareSnapshot | null | undefined) {
+  if (!snapshot) {
+    return null;
+  }
+
+  if (snapshot.detailLevel === 'initial') {
+    return snapshot;
+  }
+
+  const trimmedRequests = snapshot.requests.slice(-SHARE_ROOM_SWITCH_CACHE_REQUEST_LIMIT);
+  const requestIdSet = new Set(trimmedRequests.map((request) => request.requestId));
+  const trimmedMessages = snapshot.messages
+    .filter((message) => {
+      const requestId = message.requestId?.trim() ?? '';
+      return !requestId || requestIdSet.has(requestId);
+    })
+    .slice(-SHARE_ROOM_SWITCH_CACHE_MESSAGE_LIMIT);
+  const oldestLoadedMessageId =
+    trimmedMessages.length > 0
+      ? trimmedMessages[0]?.id ?? snapshot.oldestLoadedMessageId
+      : snapshot.oldestLoadedMessageId;
+
+  return {
+    ...snapshot,
+    detailLevel: 'initial',
+    requests: trimmedRequests,
+    messages: trimmedMessages,
+    activityLogs: [],
+    oldestLoadedMessageId,
+    hasOlderMessages: true,
+  } satisfies ChatShareSnapshot;
+}
+
+function startShareRoomSwitchPerfRun(fromSessionId: string, toSessionId: string) {
+  if (typeof window === 'undefined') {
+    return '';
+  }
+
+  const perfWindow = window as ShareWindowWithPerf;
+  const nextRun: ShareRoomSwitchPerfRun = {
+    id: `${Date.now()}-${Math.random().toString(36).slice(2, 8)}`,
+    fromSessionId: fromSessionId.trim(),
+    toSessionId: toSessionId.trim(),
+    startedAt: performance.now(),
+    steps: [],
+  };
+  const nextRuns = [...(perfWindow.__chatShareRoomSwitchPerfRuns ?? []).slice(-9), nextRun];
+  perfWindow.__chatShareRoomSwitchPerfRuns = nextRuns;
+  return nextRun.id;
+}
+
+function recordShareRoomSwitchPerfStep(
+  runId: string,
+  name: string,
+  snapshot?: ChatShareSnapshot | null,
+  extra?: Pick<ShareRoomSwitchPerfStep, 'hasCache'>,
+) {
+  if (typeof window === 'undefined' || !runId) {
+    return;
+  }
+
+  const perfWindow = window as ShareWindowWithPerf;
+  const runs = perfWindow.__chatShareRoomSwitchPerfRuns;
+
+  if (!runs?.length) {
+    return;
+  }
+
+  const targetRun = runs.find((run) => run.id === runId);
+
+  if (!targetRun) {
+    return;
+  }
+
+  targetRun.steps.push({
+    name,
+    at: performance.now(),
+    detailLevel: snapshot?.detailLevel,
+    requestCount: snapshot?.requests.length,
+    messageCount: snapshot?.messages.length,
+    activityLogCount: snapshot?.activityLogs.length,
+    hasCache: extra?.hasCache,
+  });
+}
+
 function readShareRoomSessionIdFromLocation() {
   if (typeof window === 'undefined') {
     return '';
@@ -4074,6 +4188,7 @@ export function ChatSharePage() {
     typeof window === 'undefined' || !normalizedToken
       ? null
       : readStoredShareRoomSnapshot(normalizedToken, initialRequestedRoomSessionId);
+  const initialHasCachedSnapshot = initialCachedSnapshot != null;
   const scrollContainerRef = useRef<HTMLDivElement | null>(null);
   const pageRef = useRef<HTMLDivElement | null>(null);
   const requestAnchorRefs = useRef(new Map<string, HTMLElement>());
@@ -4083,6 +4198,11 @@ export function ChatSharePage() {
   const deferredSnapshotRef = useRef<ChatShareSnapshot | null>(null);
   const liveRefreshTimerRef = useRef<number | null>(null);
   const snapshotRefreshPromiseRef = useRef<Promise<boolean> | null>(null);
+  const snapshotRefreshAbortControllerRef = useRef<AbortController | null>(null);
+  const snapshotRefreshInFlightRoomSessionIdRef = useRef('');
+  const snapshotRefreshInFlightViewRef = useRef<'initial' | 'full' | null>(null);
+  const roomSwitchPerfRunIdRef = useRef('');
+  const pendingSnapshotPerfStageRef = useRef<{ runId: string; stage: 'cache' | 'initial' | 'full' } | null>(null);
   const pendingSilentRefreshRef = useRef(false);
   const scrollSyncFrameRef = useRef<number | null>(null);
   const scrollIdleTimerRef = useRef<number | null>(null);
@@ -4232,6 +4352,21 @@ export function ChatSharePage() {
   const isRoomSwitchingRef = useRef(isRoomSwitching);
   isRoomSwitchingRef.current = isRoomSwitching;
 
+  useLayoutEffect(() => {
+    const pendingStage = pendingSnapshotPerfStageRef.current;
+
+    if (!pendingStage || !snapshot) {
+      return;
+    }
+
+    pendingSnapshotPerfStageRef.current = null;
+    recordShareRoomSwitchPerfStep(pendingStage.runId, `${pendingStage.stage}-snapshot-commit`, snapshot);
+
+    window.requestAnimationFrame(() => {
+      recordShareRoomSwitchPerfStep(pendingStage.runId, `${pendingStage.stage}-first-frame`, snapshot);
+    });
+  }, [snapshot]);
+
   const shareTokenSetting = snapshot?.share.tokenSetting ?? null;
   const shareAllowedAppIdSet = useMemo(
     () => buildShareAllowedAppIdSet(shareTokenSetting?.allowedAppIds, snapshot?.share.permissions),
@@ -4858,35 +4993,65 @@ export function ChatSharePage() {
 
     void refreshShareRuntime();
   }, [isRoomSettingsOpen, refreshShareRuntime, roomSettingsTabKey]);
-  const refreshSnapshot = useCallback(async (options?: { initialLoad?: boolean; silent?: boolean; sharePin?: string | null }) => {
+  const refreshSnapshot = useCallback(async (options?: {
+    initialLoad?: boolean;
+    silent?: boolean;
+    sharePin?: string | null;
+    view?: 'initial' | 'full';
+    preserveVisibleSnapshot?: boolean;
+  }) => {
     if (!normalizedToken) {
       return false;
     }
 
     const initialLoad = options?.initialLoad === true;
     const silent = options?.silent === true;
+    const requestView = options?.view ?? (initialLoad ? 'initial' : 'full');
+    const preserveVisibleSnapshot = options?.preserveVisibleSnapshot === true;
+    const currentPerfRunId = roomSwitchPerfRunIdRef.current;
+    const requestedSessionId = requestedRoomSessionIdRef.current.trim();
 
     if (snapshotRefreshPromiseRef.current) {
-      if (!initialLoad) {
-        pendingSilentRefreshRef.current = pendingSilentRefreshRef.current || silent;
+      const inFlightRoomSessionId = snapshotRefreshInFlightRoomSessionIdRef.current;
+      const inFlightView = snapshotRefreshInFlightViewRef.current;
+      const shouldReplaceInFlightRequest =
+        requestView === 'initial'
+        || requestedSessionId !== inFlightRoomSessionId
+        || inFlightView !== requestView;
+
+      if (shouldReplaceInFlightRequest) {
+        snapshotRefreshAbortControllerRef.current?.abort();
+      } else {
+        if (!initialLoad) {
+          pendingSilentRefreshRef.current = pendingSilentRefreshRef.current || silent;
+        }
+        return snapshotRefreshPromiseRef.current;
       }
-      return snapshotRefreshPromiseRef.current;
     }
 
+    const abortController = new AbortController();
+    snapshotRefreshAbortControllerRef.current = abortController;
+    snapshotRefreshInFlightRoomSessionIdRef.current = requestedSessionId;
+    snapshotRefreshInFlightViewRef.current = requestView;
+
     if (options?.initialLoad) {
-      setIsLoading(true);
-    } else {
+      if (!(preserveVisibleSnapshot && hasSnapshotRef.current)) {
+        setIsLoading(true);
+      }
+    } else if (!silent) {
       setIsRefreshing(true);
     }
 
-    const refreshTask = (async () => {
+    const refreshTaskPromise = (async () => {
       try {
+        recordShareRoomSwitchPerfStep(currentPerfRunId, `${requestView}-fetch-start`);
         const nextSnapshot = await fetchChatShareSnapshot(normalizedToken, {
           sharePin: options?.sharePin,
-          sessionId: requestedRoomSessionIdRef.current || undefined,
-          view: initialLoad ? 'initial' : 'full',
+          sessionId: requestedSessionId || undefined,
+          signal: abortController.signal,
+          view: requestView,
         });
-        const requestedSessionId = requestedRoomSessionIdRef.current.trim();
+        recordShareRoomSwitchPerfStep(currentPerfRunId, `${requestView}-fetch-end`, nextSnapshot);
         const matchedRequestedRoom = doesShareSnapshotMatchRequestedRoom(nextSnapshot, requestedSessionId);
 
         const shouldApplyImmediately =
@@ -4899,12 +5064,19 @@ export function ChatSharePage() {
         if (!shouldApplyImmediately) {
           deferredSnapshotRef.current = nextSnapshot;
         } else {
-          setSnapshot(nextSnapshot);
+          pendingSnapshotPerfStageRef.current = currentPerfRunId
+            ? { runId: currentPerfRunId, stage: requestView }
+            : null;
+          if (!initialLoad && requestView === 'full' && hasSnapshotRef.current) {
+            startTransition(() => {
+              setSnapshot(nextSnapshot);
+            });
+          } else {
+            setSnapshot(nextSnapshot);
+          }
           deferredSnapshotRef.current = null;
         }
-        if (nextSnapshot.detailLevel !== 'initial') {
-          writeStoredShareRoomSnapshot(normalizedToken, nextSnapshot);
-        }
+        writeStoredShareRoomSnapshot(normalizedToken, nextSnapshot);
         if (nextSnapshot.share.hasAccessPin) {
           const resolvedPin = normalizeAccessPinInput(options?.sharePin ?? '');
           const persistedPin = resolvedPin || getStoredChatShareAccessPin(normalizedToken);
@@ -4919,6 +5091,7 @@ export function ChatSharePage() {
         }
 
         if (matchedRequestedRoom) {
+          recordShareRoomSwitchPerfStep(currentPerfRunId, `${requestView}-matched-requested-room`, nextSnapshot);
           setIsRoomSwitching(false);
         } else if (requestedSessionId) {
           pendingSilentRefreshRef.current = true;
@@ -4930,6 +5103,10 @@ export function ChatSharePage() {
 
         return true;
       } catch (error) {
+        if (error instanceof DOMException && error.name === 'AbortError') {
+          return false;
+        }
+
         if (error instanceof ChatApiError && error.status === 401 && (error.code === 'share_pin_required' || error.code === 'share_pin_invalid')) {
           setStoredChatShareAccessPin(normalizedToken, null);
           clearStoredShareRoomSnapshotCache(normalizedToken);
@@ -4950,7 +5127,16 @@ export function ChatSharePage() {
         setIsRoomSwitching(false);
         return false;
       } finally {
-        snapshotRefreshPromiseRef.current = null;
+        if (snapshotRefreshAbortControllerRef.current === abortController) {
+          snapshotRefreshAbortControllerRef.current = null;
+        }
+        if (snapshotRefreshPromiseRef.current === refreshTaskPromise) {
+          snapshotRefreshPromiseRef.current = null;
+        }
+        if (snapshotRefreshInFlightRoomSessionIdRef.current === requestedSessionId) {
+          snapshotRefreshInFlightRoomSessionIdRef.current = '';
+          snapshotRefreshInFlightViewRef.current = null;
+        }
         setIsLoading(false);
         setIsRefreshing(false);
 
@@ -4963,9 +5149,40 @@ export function ChatSharePage() {
       }
     })();
 
-    snapshotRefreshPromiseRef.current = refreshTask;
-    return refreshTask;
+    snapshotRefreshPromiseRef.current = refreshTaskPromise;
+    return refreshTaskPromise;
   }, [normalizedToken]);
+  const ensureLatestShareRoomDetailLoaded = useCallback(
+    async (requestId?: string | null) => {
+      const normalizedRequestId = requestId?.trim() ?? '';
+
+      if (!normalizedToken || !snapshot?.conversation.sessionId) {
+        return;
+      }
+
+      if (
+        normalizedRequestId
+        && snapshot.activityLogs.some((item) => item.requestId.trim() === normalizedRequestId)
+      ) {
+        return;
+      }
+
+      setIsLoadingFullSnapshot(true);
+
+      try {
+        const detailPage = await fetchChatShareConversationDetail(normalizedToken, {
+          sessionId: snapshot.conversation.sessionId,
+          limit: Math.max(SHARE_ROOM_SWITCH_CACHE_REQUEST_LIMIT, snapshot.requests.length || 0),
+          sharePin: getStoredChatShareAccessPin(normalizedToken) || undefined,
+        });
+
+        setSnapshot((current) => (current ? mergeChatShareSnapshotHistory(current, detailPage) : current));
+      } finally {
+        setIsLoadingFullSnapshot(false);
+      }
+    },
+    [normalizedToken, snapshot],
+  );
   const handleLoadOlderShareHistory = useCallback(async () => {
     if (!normalizedToken || !snapshot?.conversation.sessionId || !snapshot.hasOlderMessages || !snapshot.oldestLoadedMessageId) {
       return;
@@ -5676,15 +5893,27 @@ export function ChatSharePage() {
     event.preventDefault();
   }, []);
 
-  const openProcessInspector = useCallback((requestId: string) => {
-    if (!requestId.trim()) {
+  const openProcessInspector = useCallback(async (requestId: string) => {
+    const normalizedRequestId = requestId.trim();
+
+    if (!normalizedRequestId) {
       return;
     }
 
-    setActiveProcessInspectorRequestId(requestId);
+    const hasActivityLog = snapshot?.activityLogs.some((item) => item.requestId.trim() === normalizedRequestId) ?? false;
+
+    if (!hasActivityLog) {
+      try {
+        await ensureLatestShareRoomDetailLoaded(normalizedRequestId);
+      } catch (error) {
+        message.error(error instanceof Error ? error.message : '상세 활동 로그를 불러오지 못했습니다.');
+      }
+    }
+
+    setActiveProcessInspectorRequestId(normalizedRequestId);
     setProcessInspectorMode('default');
     setProcessInspectorExpandedSection('checklist');
-  }, []);
+  }, [ensureLatestShareRoomDetailLoaded, message, snapshot?.activityLogs]);
 
   const closeProcessInspector = useCallback(() => {
     setActiveProcessInspectorRequestId('');
@@ -6083,9 +6312,13 @@ export function ChatSharePage() {
       return undefined;
     }
 
-    void refreshSnapshot({ initialLoad: true });
+    void refreshSnapshot({
+      initialLoad: true,
+      view: 'initial',
+      preserveVisibleSnapshot: initialHasCachedSnapshot,
+    });
     return undefined;
-  }, [normalizedToken, refreshSnapshot]);
+  }, [initialHasCachedSnapshot, normalizedToken, refreshSnapshot]);
   useEffect(() => {
     if (typeof window === 'undefined') {
       return;
@@ -6094,7 +6327,6 @@ export function ChatSharePage() {
     const urlRoomSessionId = readShareRoomSessionIdFromLocation();
     const restoredRoomSessionId = urlRoomSessionId || readStoredShareLastRoomSessionId(normalizedToken);
     const cachedSnapshot = readStoredShareRoomSnapshot(normalizedToken, restoredRoomSessionId);
-
     requestedRoomSessionIdRef.current = restoredRoomSessionId;
     deferredSnapshotRef.current = null;
     setSnapshot(cachedSnapshot);
@@ -6116,7 +6348,7 @@ export function ChatSharePage() {
       if (cachedSnapshot) {
         setSnapshot(cachedSnapshot);
       }
-      setIsRoomSwitching(Boolean(nextRoomSessionId));
+      setIsRoomSwitching(Boolean(nextRoomSessionId) && !cachedSnapshot);
       setRequestedRoomSessionId(nextRoomSessionId);
       setIsShareRoomListVisible(false);
     };
@@ -6137,8 +6369,15 @@ export function ChatSharePage() {
       return;
     }
 
-    void refreshSnapshot({ silent: true });
-  }, [normalizedToken, refreshSnapshot, requestedRoomSessionId]);
+    const requestedSessionId = requestedRoomSessionId.trim();
+    const hasMatchingSnapshot = doesShareSnapshotMatchRequestedRoom(snapshot, requestedSessionId);
+
+    if (hasMatchingSnapshot) {
+      return;
+    }
+
+    void refreshSnapshot({ silent: true, view: 'initial' });
+  }, [normalizedToken, refreshSnapshot, requestedRoomSessionId, snapshot]);
   useEffect(() => {
     if (!normalizedToken || !snapshot || snapshot.detailLevel === 'initial') {
       return;
@@ -6688,9 +6927,13 @@ export function ChatSharePage() {
     }
 
     const cachedSnapshot = readStoredShareRoomSnapshot(normalizedToken, normalizedSessionId);
+    const perfRunId = startShareRoomSwitchPerfRun(selectedShareRoomSessionId, normalizedSessionId);
 
     deferredSnapshotRef.current = null;
+    roomSwitchPerfRunIdRef.current = perfRunId;
+    recordShareRoomSwitchPerfStep(perfRunId, 'room-select', undefined, { hasCache: Boolean(cachedSnapshot) });
     if (cachedSnapshot) {
+      pendingSnapshotPerfStageRef.current = { runId: perfRunId, stage: 'cache' };
       setSnapshot(cachedSnapshot);
     }
     setIsRoomSwitching(!cachedSnapshot);
@@ -8366,7 +8609,11 @@ export function ChatSharePage() {
     const normalizedRoomSessionId = restoreSnapshot.roomSessionId.trim();
 
     if (normalizedRoomSessionId && normalizedRoomSessionId !== selectedShareRoomSessionId) {
-      setIsRoomSwitching(true);
+      const cachedSnapshot = readStoredShareRoomSnapshot(normalizedToken, normalizedRoomSessionId);
+      if (cachedSnapshot) {
+        setSnapshot(cachedSnapshot);
+      }
+      setIsRoomSwitching(!cachedSnapshot);
       requestedRoomSessionIdRef.current = normalizedRoomSessionId;
       writeStoredShareLastRoomSessionId(normalizedToken, normalizedRoomSessionId);
       writeShareRoomSessionIdToLocation(normalizedRoomSessionId, 'replace');
diff --git a/src/components/previewer/FullscreenPreviewModal.tsx b/src/components/previewer/FullscreenPreviewModal.tsx
index 0b2dc02..cb9c31c 100644
--- a/src/components/previewer/FullscreenPreviewModal.tsx
+++ b/src/components/previewer/FullscreenPreviewModal.tsx
@@ -5,6 +5,7 @@ import './FullscreenPreviewModal.css';
 
 type FullscreenPreviewModalProps = {
   open: boolean;
+  afterOpenChange?: (open: boolean) => void;
   title?: ReactNode;
   meta?: ReactNode;
   actions?: ReactNode;
@@ -25,6 +26,7 @@ type FullscreenPreviewModalProps = {
 
 export function FullscreenPreviewModal({
   open,
+  afterOpenChange,
   title,
   meta,
   actions,
@@ -45,6 +47,7 @@ export function FullscreenPreviewModal({
   return (
     <Modal
       open={open}
+      afterOpenChange={afterOpenChange}
       footer={null}
       title={null}
       width="100vw"
diff --git a/src/views/play/apps/baseball-ticket-bay/BaseballTicketBayPlayAppView.tsx b/src/views/play/apps/baseball-ticket-bay/BaseballTicketBayPlayAppView.tsx
index d259ca4..abfb59b 100644
--- a/src/views/play/apps/baseball-ticket-bay/BaseballTicketBayPlayAppView.tsx
+++ b/src/views/play/apps/baseball-ticket-bay/BaseballTicketBayPlayAppView.tsx
@@ -2056,11 +2056,6 @@ export function BaseballTicketBayPlayAppView({ onBack, launchContext = 'direct',
               <span>{alerts.length}건</span>
             </div>
           </div>
-          {isViewingAllClients || isSharedTokenScope ? (
-            <div className="baseball-ticket-bay-app__scope-note">
-              {isSharedTokenScope ? '현재 공유 리소스 별명 기준으로 목록을 표시합니다.' : '등록 토큰으로 전체 기기 목록을 보고 있습니다. 리소스 별명으로 확인하고 수정과 삭제도 바로 할 수 있습니다.'}
-            </div>
-          ) : null}
           <div className="baseball-ticket-bay-app__items">
             {alerts.length ? (
               alerts.map((item) => {