Environment

• OpenClaw Version: 2026.2.17
• OS: macOS 15.3 (Tahoe)
• Browser: Chrome 145.0.7632.77
• Gateway: Running as LaunchAgent on 127.0.0.1:18789

Issue Summary

The dashboard's /chat page becomes unresponsive (Chrome shows "Page Unresponsive") when the session history contains many messages. This creates a poor user experience and makes the dashboard unusable for power users with extended conversations.

Symptoms

1. Chat page hangs: The /chat page frequently causes Chrome to show "Page Unresponsive" dialog
2. No streaming: Chat shows thinking indicator (...) but never streams the response in real-time
3. WebSocket disconnects: Gateway logs show repeated WebSocket connect/disconnect cycles (code=1001)
4. Other pages work fine: Overview and other dashboard pages load normally

Root Cause Analysis

After investigation, we found:

• Current session had 292 messages totaling 1.5MB
• Some archived sessions were up to 8.2MB
• The chat UI appears to load and render the entire message history at once
• This causes Chrome to hang when rendering large histories

Gateway Logs (WebSocket disconnects)

[ws] webchat disconnected code=1001 reason=n/a
[ws] webchat connected conn=...
[ws] webchat disconnected code=1001 reason=n/a  (2-4 seconds later)
[ws] webchat connected conn=...

The rapid connect/disconnect cycle (code=1001 = client-initiated "Going Away") suggests the browser is killing the tab due to unresponsiveness, then the UI tries to reconnect.

Workaround

Archiving large session files (>1MB) to a separate directory fixes the issue:

mkdir -p ~/.openclaw/agents/main/sessions/archive
mv ~/.openclaw/agents/main/sessions/<large-session>.jsonl ~/.openclaw/agents/main/sessions/archive/
openclaw gateway restart

Suggested Fixes

1. Virtualized list rendering: Use virtual scrolling (e.g., react-window, @tanstack/virtual) to only render visible messages
2. Pagination: Load messages in chunks (e.g., last 50 messages, load more on scroll up)
3. Lazy loading: Don't fetch full message content until user scrolls to it
4. Message truncation: Collapse large tool outputs by default, expand on click
5. Session size warning: Alert users when session is getting large, suggest archiving

Additional Context

• Also encountered Issue 1 (resolved): CSS contained Google Fonts @import that was blocked by gateway's CSP (font-src 'self'), causing blank page. Fixed by manually stripping the import.

Reproduction Steps

1. Use OpenClaw extensively via iMessage/Telegram (accumulate 200+ messages)
2. Open dashboard at http://127.0.0.1:18789/
3. Navigate to /chat
4. Observe page becoming unresponsive

Labels

bug, dashboard, performance