When the nested session deletion button is unchecked the session still disapp...

When the nested session deletion button is unchecked the session still disappears along with the main session

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| Field | Value |
| --- | --- |
| App version | 1.0.22 |
| OS | macOS 26.5.2 |
| Theme | GitHub |
| Path | /chat |
| Tenure | Week 9 |

Start by reproducing the issue on /chat with the nested session deletion option unchecked, using the reported macOS environment if available. Confirm the main session can be deleted while the nested session remains; the issue is done when that behavior is reliable.

索引モデルが issue の本文から書いたものです。