[BUG] Claude desktop app freezes when copying a color code in KolourPaint after pasting a shared screenshot

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?

Environment: Zorin OS 18.1 (Linux, kernel 7.0.0-31-generic, Ubuntu 24.04 base), Claude desktop app (Code tab)
Steps to reproduce:

Have an active Claude Code chat with a screenshot already shared/visible in it.
Copy that same screenshot and paste it (Ctrl+V) into KolourPaint.
In KolourPaint, select/adjust a color (both hue and opacity).
Copy the selected color code (Ctrl+C).
Result: Both KolourPaint and the Claude app freeze completely at that point — neither responds to anything anymore. Only a full restart of the Claude app helped (needed it twice).
Positive note: after restarting, no data was lost — the chat/memory correctly restored to exactly where it left off.
Additional info to fill in yourself: whether this reproduces every time with these exact steps, or only sometimes.

OS:
Distro: Zorin OS 18.1 (based on Ubuntu 24.04, noble)
Kernel: 7.0.0-31-generic (x86_64)
Running environment: Flatpak sandbox "Freedesktop SDK 25.08" (host accessed via mounts)
Hostname: SENSORED — uptime: 1 day, 13h 34m

Hardware:
CPU: AMD Ryzen 9 7950X3D — 16 cores / 32 threads, max boost ~5.7 GHz, 128 MiB L3 cache
RAM: 32 GiB total (16 GiB in use), 2 GiB swap
GPU(s):
NVIDIA GeForce RTX 4080 SUPER (AD103)
AMD Radeon iGPU (Raphael, integrated)
Storage: 1.8 TB NVMe SSD (nvme0n1, 2 partitions)
Network: MediaTek MT7922 Wi-Fi 6E adapter

What Should Happen?

thats up to you

Error Messages/Logs

none

Steps to Reproduce

Have an active Claude Code chat with a screenshot already shared/visible in it.
Copy that same screenshot and paste it (Ctrl+V) into KolourPaint.
make some changes in klourpaint.
In KolourPaint, select/adjust a color (both hue and opacity).
Copy the selected color code (Ctrl+C).
go back to claude
and paste the color code. and thats what causes the freeze
Result: Both KolourPaint and the Claude app freeze completely at that point — neither responds to anything anymore. Only a full restart of the Claude app helped (needed it twice).
Positive note: after restarting, no data was lost — the chat/memory correctly restored to exactly where it left off.
Additional info to fill in yourself: this reproduces every time with these exact steps

watch the video with key en mouse records
https://www.swisstransfer.com/dl/01a0bccc-da68-72be-9e3c-49ca0d74cfbc
30 day limit before video gets deleted

or pm me ill keep video on my drive and redo process

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

Flatpack sandbox block

Claude Code Version

Flatpack sandbox block

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

watch the video with key en mouse records
https://www.swisstransfer.com/dl/01a0bccc-da68-72be-9e3c-49ca0d74cfbc
30 day limit before video gets deleted

or pm me ill keep video on my drive and redo process