diff --git a/ui/src/ui/app-chat.ts b/ui/src/ui/app-chat.ts
index dc8eaf39be6..d06c87a068c 100644
--- a/ui/src/ui/app-chat.ts
+++ b/ui/src/ui/app-chat.ts
@@ -356,8 +356,8 @@ export async function refreshChat(host: ChatHost, opts?: { scheduleScroll?: bool
   await Promise.all([
     loadChatHistory(host as unknown as OpenClawApp),
     loadSessions(host as unknown as OpenClawApp, {
-      activeMinutes: 0,
-      limit: 0,
+      activeMinutes: CHAT_SESSIONS_ACTIVE_MINUTES,
+      limit: 40,
       includeGlobal: true,
       includeUnknown: true,
     }),
diff --git a/ui/src/ui/controllers/chat.ts b/ui/src/ui/controllers/chat.ts
index f2fccf57f92..1536a1114a0 100644
--- a/ui/src/ui/controllers/chat.ts
+++ b/ui/src/ui/controllers/chat.ts
@@ -71,21 +71,27 @@ export async function loadChatHistory(state: ChatState) {
   state.chatLoading = true;
   state.lastError = null;
   try {
+    // Request a small batch to avoid huge payloads and main-thread freeze when
+    // parsing JSON and rendering many markdown messages (browser "tab unresponsive").
+    const CHAT_HISTORY_REQUEST_LIMIT = 25;
     const res = await state.client.request<{ messages?: Array<unknown>; thinkingLevel?: string }>(
       "chat.history",
       {
         sessionKey: state.sessionKey,
-        limit: 200,
+        limit: CHAT_HISTORY_REQUEST_LIMIT,
       },
     );
     const messages = Array.isArray(res.messages) ? res.messages : [];
-    state.chatMessages = messages.filter((message) => !isAssistantSilentReply(message));
+    const filtered = messages.filter((message) => !isAssistantSilentReply(message));
     state.chatThinkingLevel = res.thinkingLevel ?? null;
-    // Clear all streaming state — history includes tool results and text
-    // inline, so keeping streaming artifacts would cause duplicates.
     maybeResetToolStream(state);
     state.chatStream = null;
     state.chatStreamStartedAt = null;
+    // Defer applying messages so the UI can paint "Loading chat..." before the heavy render.
+    state.chatLoading = false;
+    requestAnimationFrame(() => {
+      state.chatMessages = filtered;
+    });
   } catch (err) {
     state.lastError = String(err);
   } finally {
diff --git a/ui/src/ui/views/chat.ts b/ui/src/ui/views/chat.ts
index 88a712706f0..077b3c3bd87 100644
--- a/ui/src/ui/views/chat.ts
+++ b/ui/src/ui/views/chat.ts
@@ -1328,7 +1328,8 @@ export function renderChat(props: ChatProps) {
   `;
 }
 
-const CHAT_HISTORY_RENDER_LIMIT = 200;
+// Cap rendered history to avoid main-thread freeze (markdown + DOM for each message).
+const CHAT_HISTORY_RENDER_LIMIT = 25;
 
 function groupMessages(items: ChatItem[]): Array<ChatItem | MessageGroup> {
   const result: Array<ChatItem | MessageGroup> = [];