[Error] [GitHub.copilot-chat] unhandlederror-Error in extension github.copilot-chat: FAILED to handle event: Cannot read propertie...

## Error Message
````
unhandlederror-Error in extension github.copilot-chat: FAILED to handle event: Cannot read properties of undefined (reading 'startOffset')
````

## Stack Trace
    at KOr (../src/platform/notebook/common/alternativeNotebookTextDocument.ts:398:93)
    at withNotebookChangesAndEdit (../src/platform/notebook/common/alternativeNotebookTextDocument.ts:448:8)
    at MessagePortMain.emit (node:events:509:28) [not deminified]
    at Object.emit (node::2:2934) [not deminified]

Raw Stack Trace (minified)

````
TypeError: Cannot read properties of undefined (reading 'startOffset') at KOr ( VS /resources\app\extensions\copilot\dist\extension.js:3510:6193) at e9r ( VS /resources\app\extensions\copilot\dist\extension.js:3510:6677) at VS /resources\app\extensions\copilot\dist\extension.js:3510:13893 at MessagePortMain.emit (node:events:509:28) at Object.emit (node::2:2934)
````

## Details
| Property | Value |
| --- | --- |
| Bucket ID | [`0943b5af-a65c-6c65-0d41-f07e2a67ebfe`](https://errors.code.visualstudio.com/bucket/0943b5af-a65c-6c65-0d41-f07e2a67ebfe?product=VSCode&extension=GitHub.copilot-chat&commit=8a7abeba6e03ea3af87bfbce9a1b7e48fed567b8) |
| Extension Version | 0.57.0 |
| Last Seen | Sun Jul 19 2026 23:19:59 GMT+0000 (Coordinated Universal Time) |
| Platforms | win32 |
| Product | VSCode |

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