Bug: Arena Mode exit discards Thread B messages silently when verdict is Tie

[huzaifaWD20]

What happened?

Describe the bug
When exiting Arena Mode after selecting Tie as the verdict (or any verdict other than Model A winning), Thread B's messages are silently discarded. The chat continues with only Model A's response. The user loses Thread B content with no explanation or warning.

Actual behavior
Thread B messages are silently discarded regardless of verdict. Chat continues with Model A only. No explanation given to user.

Steps to reproduce

Steps to reproduce

1. Open AI Chat and activate Arena Mode
2. Select two different models
3. Send a message and receive two responses
4. Select Tie as the verdict
5. Exit Arena Mode
6. Observe the chat — only Model A response is present

Expected behavior

Expected behavior
On exit with a Tie verdict, the user should either be informed which thread continues, or both responses should be preserved. If a non-A model wins the verdict, that model's messages should be merged into the continuing thread as described in the v0.2.40 changelog.

Affected service

Platform

Version or commit

v0.2.46

Browser and OS

No response

Relevant log output

Screenshots or recordings

No response

Before submitting

• I searched existing issues and this hasn't been reported yet.

[yannickmonney]

Thanks @huzaifaWD20. This matches the intended Arena design. In Arena mode, Thread B is an ephemeral comparison branch: its messages are merged into the main thread (A) only when the verdict is "B is better". For "A is better", "Tie", or "both bad", A is kept and B is discarded as an internal artifact (it never enters Trash). The v0.2.40 notes describe exactly this ("messages merge into A when B wins the verdict"), so a Tie keeping only A is correct, not data loss.

The one reasonable UX point is showing a brief confirmation/toast before B is discarded — I've noted that as a minor enhancement. Closing the data-loss framing as working-as-intended.