Yes, the CSS has :hover classes, for example: .PlayPauseButton:hover { color: #FF0; text-decoration: none; cursor: pointer; } When i run this HTML/CSS in Safari, or in a normal WKWebView in a test app, it all works normally.

Another issue: WKWebView-based screensaver doesn't display on 2nd monitor (legacyScreenSaver) in Tahoe Submitted as # FB17938870

Testing using Beta 3, I've figured out one of the issues: In macOS Tahoe, when you are viewing the Screen Savers dialog (from inside Wallpaper), using legacyScreenSaver, the system is incorrectly launching 2 copies - one at fullscreen on the main screen, and then a second (correct) instance which is in Preview mode. Reported as FB18697726

I have also submitted a case regarding the regressions in UI/UX for screensavers: Tahoe has redesigned the UI for System Settings to remove the Screen Saver pane altogether. Instead, you access Screen Savers from within the Wallpaper settings. This has the following issues: Confusion - macOS has emphasized the importance of Screen Saves in recent years, and users expect to have a Screen Saver pane Usability - although you can access the Screen Savers settings, it’s now hidden behind a button within the Wallpaper settings, and the resulting window runs as a very small modal non-resizable dialog. Since macOS ships with dozens of screensavers by default, forcing the user to navigate these in a tiny window is just silly. Backwards compatibility is broken. For example, the command open x-apple.systempreferences:com.apple.ScreenSaver-Settings.extension No longer works in Tahoe. FB18698083

FYI, we just tested beta 5 (25A5327h) and aren't seeing any improvements or changes.

To update an old issue - without any project changes on my end, but with several Xcode upgrades, this stopped happening. I don't know the exact Xcode version when it stopped.