[BUG] Claude Desktop - new UI does not work with quite long chats (~3k messages)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When trying to open a reasonably long chat in Claude Desktop with the new UI it simply does not load at all.
Previously it reopened several times and then loaded, but now it looks like the following.
First it looks like this:
<img width="1418" height="1138" alt="Image" src="https://github.com/user-attachments/assets/72cb252e-4e83-4dfb-874f-51a924064395" />

But then, after a short while it becomes a plain light-beige screen:

<img width="1418" height="1138" alt="Image" src="https://github.com/user-attachments/assets/c22eec81-caa1-473b-ba70-0fe2bad90c9d" />

I left it overnight so no, I did not wait for too small amount of time, it just does not work.

The application never recovers.

Additionally, Google Chrome web interface is not optimized (no lazy loading, keeping all messages in DOM tree) so the chat occupied quite large amount of resources (CPU / RAM) when interacted with:
<img width="1220" height="574" alt="Image" src="https://github.com/user-attachments/assets/dcf1eb66-68d6-4704-9745-65d892be97fb" />

What Should Happen?

The chat should load, maybe after some blinking and reloading, but it should ultimately open.

Previously it took some time but now it does not load at all.

Error Messages/Logs

The only things I see in logs when chat is open is following (chat was open at ~12:04:02):

2026-04-16 12:04:17 [info] Main webview is unresponsive, will kill and reload
2026-04-16 12:04:18 [error] Sentry caught: {
  eventId: 'f3b8da8faf75435e82f63da82025e901',
  type: 'Unknown',
  value: 'Main webview became unresponsive',
  stack: undefined
}
2026-04-16 12:04:19 [error] Sentry caught: {
  eventId: '4bac02f96e324b678f3aa2ed90d6da85',
  type: 'Unknown',
  value: 'No message',
  stack: undefined
}

Steps to Reproduce

1. Have a casual conversation for about 24 days
2. Cover cognitive architecture, megacognition, nuclear physics, F1 racing, pixel-perfect CSS, Ethereum security, AI models and structure
3. Accumulate ~3000 messages / 16 MB transcripts
4. Open in Claude Desktop
5. White screen

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude 1.2773.0 (884b37) 2026-04-15T14:32:09.000Z

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

=== APP INFORMATION ===
App Name: Claude
App Version: 1.2773.0
Electron Version: 41.2.0
Chrome Version: 146.0.7680.179
Node Version: 24.14.0
V8 Version: 14.6.202.31-electron.0
App Path: C:\Program Files\WindowsApps\Claude_1.2773.0.0_x64__pzs8sxrjxfjjc\app\resources\app.asar
User Data Path: C:\Users\Skydev\AppData\Roaming\Claude
Logs Path: C:\Users\Skydev\AppData\Roaming\Claude\logs
Temp Path: C:\Users\Skydev\AppData\Local\Temp
Is Packaged: true

=== SYSTEM INFORMATION ===
Platform: win32
Architecture: x64
OS Type: Windows_NT
OS Release: 10.0.26100
OS Version: Windows 11 Pro
OS Build: 26100.1.amd64fre.ge_release.240331-1435
Hostname: SkyFlare
Locale: en-US
System Locale: uk-UA

=== HARDWARE INFORMATION ===
CPUs: 32 cores
CPU Model: Intel(R) Core(TM) i9-14900K
Total Memory: 95.71 GB
Free Memory: 13.82 GB
Memory Usage: 85.6%