I know why black, because I use webView?.translatesAutoresizingMaskIntoConstraints = false to avoid some wkwebview bug in Xcode 13.x; now this code make black screen bug, remove it, black screen disappeared. but new bug appeared: after enter fullscreen again, the WebView become small size that same as main window. headache~~

Maybe this is Why my bug: https://developer.apple.com/forums/thread/720612