When you have multiple photos open in Camera Raw 8.4, the swap button becomes disabled, and the expected "before" state becomes unavailable.
This issue affects Camera Raw 8.4 when used with Creative Cloud applications. This issue did not affect Creative Suite 6 or Elements applications.
- Keep Photoshop up-to-date
- Direct link to Camera Raw updates for Mac and Windows
- Having trouble installing Camera Raw updates? See this article
- See this blog post for more information