As you see in the image, when I fullscreen in WKWebView, it shows black instead of the webpage in full screen. It works fine in Sequoia. It has happened to me since beta 1, but I post it now, because we’re in beta 8 and it’s not fixed. What’s going on? Can somebody tell me if they have the same issue?
Our engineering teams need to investigate this issue, as resolution may involve changes to Apple's software. Please file a bug report, include a small Xcode project and some directions that can be used to reproduce the problem, and post the Feedback number here once you do. If you post the Feedback number here I'll check the status next time I do a sweep of forums posts where I've suggested bug reports.
Bug Reporting: How and Why? has tips on creating your bug report.