for sometime, preview is "collapsed", see attached snapshot
Xcode 16.0 - sometimes preview "collapsed"
still reproducible after updated to Xcode 16 beta 4
Have you filed for an FB number? Can you share the FB number on this post for other people who are having the same issue?
Otherwise, please report it using the Feedback Assistant. Don't forget to include as much information as you can, reproducible steps, and if possible, the project that is causing the issue. Once you open the bug report, please post the FB number here for my reference.
If you have any questions about filing a bug report, take a look at Bug Reporting: How and Why?