[Bug] Text corruption when copying large terminal selections in KDE Konsole

Bug Description

I am experiencing repeatable text corruption when copying larger amounts of conversation history from one specific Claude Code project running in KDE Konsole.

The problem is consistently reproducible in this existing project and its conversation history. However, I have not been able to reproduce it in newly created Claude Code projects or fresh conversations.

This suggests that the issue may depend on something specific to the stored project session, its conversation history, the reconstruction of that history, or an interaction between Claude Code’s TUI and KDE Konsole.

Environment

• CachyOS / Arch Linux
• KDE Plasma
• Wayland session
• KDE Konsole
• Claude Code version: 2.1.220

Steps to reproduce in the affected project

1. Open or resume the affected Claude Code project and its existing conversation.
2. Select a relatively large section of the displayed conversation history.
3. Copy the selection using KDE Konsole’s normal copy function.
4. Paste the clipboard contents into a text editor or another application.
5. Compare the pasted text with the text displayed in Claude Code.
6. Repeat the operation by copying the same content in two smaller sections.

Observed behavior

In the affected project, copying a larger section in one operation consistently produces scattered omissions.

The text is not simply truncated at the end. Instead, fragments from the middle of multiple lines disappear, and the remaining fragments are sometimes joined together directly.

Examples from the corrupted clipboard output:

• praktisch nur abhängig von der Fens rund

Expected:

praktisch nur abhängig von der Fensterfläche. Das sind bei 60 Hz rund

• Die Sumn

Expected:

Die Summe allein ist irreführend — in

• Ändert si, wird

Expected:

Ändert sich irgendwo eine einzige Zahl, wird

The issue also affects my own prompts as displayed in the Claude Code conversation history, not only Claude’s responses.

Because the remaining fragments are joined together, the corrupted result can sometimes still appear superficially plausible and may be difficult to notice.

Project-specific behavior

The issue is consistently reproducible in one specific existing Claude Code project.

I tested newly created Claude Code projects and fresh conversations, but I could not reproduce the problem there.

Reopening the affected project and conversation does not remove the issue. The same conversation history continues to produce corrupted clipboard output when copied in a sufficiently large section.

Important observations

1. The issue is consistently reproducible in one specific existing Claude Code project.
2. I have not reproduced it in newly created projects or fresh conversations.
3. I asked Claude Code to write the same prompt to a Markdown file. The resulting file was complete and contained none of the missing fragments.
4. Copying the same terminal content in two smaller sections works correctly.
5. Copying the larger section in one operation produces scattered omissions.
6. Restarting Claude Code did not resolve the issue.
7. Closing and reopening KDE Konsole did not resolve the issue.
8. Rebooting the entire computer did not resolve the issue.
9. Reopening the affected Claude Code project and conversation does not remove the problem.
10. Claude Code is idle while the text is being selected and copied.
11. The affected conversation history contains Claude responses, user prompts, and recap text.
12. No error message is displayed.

Expected behavior

Copying selected Claude Code conversation history should preserve all displayed text without silently omitting fragments.

Actual behavior

With sufficiently large selections from the affected project, fragments from multiple lines are silently omitted.

The clipboard content is not merely cut off after a certain length. Instead, separate fragments from within many lines disappear, while later parts of those lines remain and are joined to the preceding text.

Copying the same content in smaller sections does not produce the corruption.

Current workaround

I either ask Claude Code to write important text to a file or copy the terminal output in several smaller sections.

Writing the text to a Markdown file has produced complete and correct content.

Additional assessment

The complete Markdown file strongly suggests that the underlying conversation content is intact.

Because the problem currently occurs only in one existing project, it may be related to:

• the stored conversation history,
• reconstruction of an existing session,
• terminal reflow or scrollback handling,
• Claude Code’s TUI rendering,
• KDE Konsole’s handling of large selections,
• or an interaction between Claude Code and KDE Konsole triggered by this particular project history.

I have not yet determined the exact cause.

Environment Info

• Platform: linux
• Terminal: konsole
• Version: 2.1.220
• Feedback ID: 94269fae-c3b3-40ca-9662-7b674c51309f

Errors

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