# Clicking agent thinking trace freezes Cursor: “The window is not responding” (Glass / workbench.glass.main.js)

**URL:** <https://forum.cursor.com/t/clicking-agent-thinking-trace-freezes-cursor-the-window-is-not-responding-glass-workbench-glass-main-js/167835>\
**Category:** Bug Reports\
**Tags:** chat, crashes, agents-window\
**Created:** [August 9, 2026, 5:10pm UTC](https://forum.cursor.com/t/clicking-agent-thinking-trace-freezes-cursor-the-window-is-not-responding-glass-workbench-glass-main-js/167835 "2026-08-09T17:10:47Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Jakobi\_Haskell](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@Jakobi\_Haskell](https://forum.cursor.com/u/Jakobi_Haskell)\
**Post date:** [August 9, 2026, 5:10pm UTC](https://forum.cursor.com/t/clicking-agent-thinking-trace-freezes-cursor-the-window-is-not-responding-glass-workbench-glass-main-js/167835/1 "2026-08-09T17:10:47Z")

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### Where does the bug appear (feature/product)?

Cursor IDE

### Describe the Bug

On macOS, clicking an Agent **thinking / thought trace** accordion frequently freezes the Cursor window. macOS then shows **“The window is not responding”** (Reopen / Close / Keep Waiting).

This reproduces often when expanding thinking traces after an agent turn.

Logs from the exact incident (screenshot timestamp ~09:54 local) show the renderer main thread blocked, then `CodeWindow: detected unresponsive`, with all unresponsive samples stuck in a recursive call stack inside `workbench.glass.main.js` (`Kao` repeatedly):

```auto
2026-08-09 09:53:55.988 [warning] [RendererPing] window 2 (pid 18112) blocked for ~15008ms
2026-08-09 09:54:01.315 [error] CodeWindow: detected unresponsive
2026-08-09 09:54:09.215 [error] CodeWindow unresponsive samples:
<1>
    at Kao (.../workbench.glass.main.js:379:23304)
    at Kao (.../workbench.glass.main.js:379:23497)
    at Kao (.../workbench.glass.main.js:379:23518)
    ... (same recursive Kao frames across all 7 samples)
Total Samples: 7

```

### Steps to Reproduce

1. Open Cursor IDE on macOS (Agents / Glass UI).
2. Run an Agent chat that produces a thinking / thought process block (thinking model).
3. After the thought finishes (or while reviewing the transcript), click the thinking / thought accordion to expand the trace.
4. Observe the UI freeze; macOS presents ‚The window is not responding.

### Expected Behavior

Expanding a thinking trace should open the thought content without freezing or making the window unresponsive.

### Screenshots / Screen Recordings

 ![download.png](https://us1.discourse-cdn.com/cursor1/original/3X/0/4/045f2304f245a63d771addce4f839603b7d6b5b6.png)

### Operating System

MacOS

### Version Information

Version: 3.15.6  
VSCode Version: 1.128.0  
Commit: a1f686545fd0ce8917bbd2449f733551a9bce420  
Date: 2026-08-06T01:41:03.876Z  
Electron: 40.10.3  
Chromium: 144.0.7559.236  
OS: Darwin arm64 24.6.0  
macOS: 15.7.4 (24G517)  
Hardware: Apple M4 Max, 36 GB

### For AI issues: which model did you use?

Occurs when reviewing agent thinking traces (not model-specific in my experience; happens when clicking the thought UI). Happy to attach a Request ID from a specific chat if useful.

### For AI issues: add Request ID with privacy disabled

Not captured for this UI hang (freeze happens on click in the client, before/without a new network request). Can provide one from an affected chat on request.

### Additional Information

`~/Library/Application Support/Cursor/User/globalStorage/state.vscdb` is currently **~2.0 GB** (globalStorage total ~3.5 GB). Sharing in case storage bloat interacts with Glass thinking-trace expand/render.

- User MCP servers configured (5): vercel, TalkToFigma, posthog, supabase, langfuse-docs (plus Cursor plugins).
- After the unresponsive detection, extension hosts exited and `[LocalAgentStorage]` rescanned agent DBs (69 agent headers), consistent with a window recovery/reopen path.
- Hang is correlated with expanding thinking UI in Glass (`workbench.glass.main.js`), not with a backend “Planning next moves” stall.

### Does this stop you from using Cursor

Yes - Cursor is unusable

---

<div class="post-metadata">

**Author:** ![mohitjain](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/mohitjain/32/100229_2.png) [@mohitjain](https://forum.cursor.com/u/mohitjain)\
**Post date:** [August 10, 2026, 12:02pm UTC](https://forum.cursor.com/t/clicking-agent-thinking-trace-freezes-cursor-the-window-is-not-responding-glass-workbench-glass-main-js/167835/7 "2026-08-10T12:02:51Z")

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Hey @Jakobi_Haskell ,  
Expanding a thinking trace shouldn’t freeze the window like that. We’ve let the team know and this is an issue we’re tracking.

While we dig in: close any large or minified files open in the Agents window with word wrap on, and set Editor: Wrapping Strategy to `simple` in Settings (or `"editor.wrappingStrategy": "simple"` in `settings.json`). If VoiceOver or another accessibility tool is on, try with it off.

To help us reproduce, could you share:

1. Your `editor.wrappingStrategy` and `editor.accessibilitySupport` values
2. Which editor / diff / Output tabs were open when it froze
3. Whether it still happens after a full quit (Cmd+Q) and reopen with only that chat open (no other file tabs)

I’ll post here when there’s an update.