In the diff view, if you expand an "unmodified lines" section, when you selec...

In the diff view, if you expand an "unmodified lines" section, when you select a range of lines for review, that range can't straddle the original "unmodified lines" boundary that no longer exists.

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| Field | Value |
| --- | --- |
| App version | 1.0.26 |
| OS | Windows 10.0.22631 |
| Theme | Fox |
| Path | /chat |
| Tenure | Week 3 |

Start by reproducing the selection behavior in the diff view on the reported Windows setup: expand an "unmodified lines" section, then select a range crossing its former boundary. Trace the diff-view selection handling and add coverage showing that the expanded range can be selected across that boundary; done means the range is accepted for review.

索引モデルが issue の本文から書いたものです。