fix: harden chat history lifecycle edges

ui/src/pages/chat/chat-pane.test.ts

@@ -732,6 +732,7 @@ describe("chat pane catalog session lifecycle", () => {
     pane.hasOlderMessages = vi.fn(() => true);
     pane.loadOlderMessages = vi.fn(async () => undefined);
     vi.stubGlobal("IntersectionObserver", undefined);
+    vi.stubGlobal("TouchEvent", undefined);
     const thread = document.createElement("div");
     const event = new WheelEvent("wheel", { deltaY: -1 });
     Object.defineProperty(event, "currentTarget", { value: thread });
@@ -825,6 +826,27 @@ describe("chat pane native history pagination", () => {
     }
   });
 
+  it("does not consume bootstrap history while disconnected", () => {
+    const client = { request: vi.fn() } as unknown as GatewayBrowserClient;
+    const { pane, state } = createTestChatPane({ client, sessions: {} as SessionCapability });
+    state.connected = false;
+    state.chatHistoryPagination = { hasMore: true, nextOffset: 2, totalMessages: 4 };
+    const construct = vi.fn();
+    class FakeIntersectionObserver {
+      constructor() {
+        construct();
+      }
+      disconnect() {}
+      observe() {}
+    }
+    vi.stubGlobal("IntersectionObserver", FakeIntersectionObserver);
+
+    pane.syncHistoryObserver();
+
+    expect(construct).not.toHaveBeenCalled();
+    expect(pane.historyAutoLoadBlocked).toBe(false);
+  });
+
   it("stops non-scrollable bootstrap after one older page", async () => {
     const request = vi.fn(async () => ({
       messages: [nativeHistoryMessage(3), nativeHistoryMessage(4)],

ui/src/pages/chat/chat-pane.ts

@@ -979,6 +979,7 @@ class ChatPane extends OpenClawLightDomElement {
     }
     if (
       typeof IntersectionObserver !== "function" ||
+      !this.state?.connected ||
       this.loadingOlder ||
       !this.hasOlderMessages()
     ) {
@@ -1089,7 +1090,7 @@ class ChatPane extends OpenClawLightDomElement {
     let upward =
       (event instanceof WheelEvent && event.deltaY < 0) ||
       (event instanceof KeyboardEvent && CHAT_HISTORY_UPWARD_KEYS.has(event.key));
-    if (event instanceof TouchEvent) {
+    if (typeof TouchEvent !== "undefined" && event instanceof TouchEvent) {
       const touchY = event.touches[0]?.clientY ?? null;
       if (event.type === "touchstart") {
         this.historyTouchY = touchY;

ui/src/pages/chat/session-message-cache.test.ts

@@ -148,6 +148,42 @@ describe("session message cache", () => {
     expect(snapshot?.pagination).toEqual({ hasMore: false, totalMessages: 140 });
   });
 
+  it("keeps the newer same-depth snapshot when a stale pane saves later", () => {
+    const host = createHost();
+    const cache: ChatMessageCache = new Map();
+    const current = [1, 2, 3].map((seq) => ({
+      content: `current-${seq}`,
+      __openclaw: { seq },
+    }));
+    cacheChatSessionSnapshot(
+      cache,
+      host,
+      { sessionKey: "home" },
+      {
+        messages: current,
+        pagination: { hasMore: false, totalMessages: 3 },
+        sessionId: "session-1",
+      },
+    );
+
+    cacheChatSessionSnapshot(
+      cache,
+      host,
+      { sessionKey: "home" },
+      {
+        messages: current.slice(0, 2),
+        pagination: { hasMore: true, nextOffset: 2, totalMessages: 3 },
+        sessionId: "session-1",
+      },
+    );
+
+    expect(readChatSessionSnapshot(cache, host, { sessionKey: "home" })).toEqual({
+      messages: current,
+      pagination: { hasMore: false, totalMessages: 3 },
+      sessionId: "session-1",
+    });
+  });
+
   it("does not retain history across backing session changes", () => {
     const host = createHost();
     const cache: ChatMessageCache = new Map();

ui/src/pages/chat/session-message-cache.ts

@@ -205,6 +205,15 @@ function mergeRetainedSessionDepth(
   const incomingBounds = transcriptSequenceBounds(incoming.messages);
   const existingTotal = existing.pagination.totalMessages;
   const incomingTotal = incoming.pagination.totalMessages;
+  if (
+    existingBounds &&
+    incomingBounds &&
+    typeof existingTotal === "number" &&
+    incomingTotal === existingTotal &&
+    incomingBounds.newest < existingBounds.newest
+  ) {
+    return existing;
+  }
   if (
     !existingBounds ||
     !incomingBounds ||
@@ -212,7 +221,6 @@ function mergeRetainedSessionDepth(
     typeof incomingTotal !== "number" ||
     incomingTotal < existingTotal ||
     incomingBounds.oldest <= existingBounds.oldest ||
-    incomingBounds.newest < existingBounds.newest ||
     incomingBounds.oldest > existingBounds.newest + 1
   ) {
     return incoming;