My iOS app uses a WKWebView with a WKUIDelegate method (webView:createWebViewWithConfiguration:forNavigationAction:windowFeatures:) to handle popup windows. This works for most cases, but during OAuth flows on certain sites (e.g., canva.com), the popup WKWebView attempts to send results back to the main WKWebView using JavaScript like window.opener.postMessage(...). However, window.opener is always null in the popup, preventing the message from being posted and blocking login completion.I've researched this and found suggestions that it's by design, as WKWebView instances are isolated for security reasons. Has anyone encountered this and found a reliable workaround (e.g., bridging communication between the main and popup WKWebViews without relying on window.opener)?