The outline panel flickers when searching or when the file content
changes. This happens because an empty UI appears during the search
process, but it only lasts for a few milliseconds, so we can safely
ignore it.

## Before

https://github.com/user-attachments/assets/9b409827-75ee-4a45-864a-58f0ca43191f

## After

https://github.com/user-attachments/assets/b6d48143-1f1a-4811-8754-0a679428eec2

Release Notes:

- N/A