diff --git a/Sources/BrowserWindowPortal.swift b/Sources/BrowserWindowPortal.swift
index 6677ba91..97d90f6a 100644
--- a/Sources/BrowserWindowPortal.swift
+++ b/Sources/BrowserWindowPortal.swift
@@ -2390,7 +2390,28 @@ final class WindowBrowserPortal: NSObject {
                 reason: reason
             )
         }
+        func preserveVisibleDuringTransientDetach(reason: String) -> Bool {
+            guard entry.visibleInUI, !containerView.isHidden else { return false }
+            let didScheduleTransientRecovery = scheduleTransientRecoveryRetryIfNeeded(
+                forWebViewId: webViewId,
+                entry: &entry,
+                webView: webView,
+                reason: reason
+            )
+            guard didScheduleTransientRecovery else { return false }
+#if DEBUG
+            dlog(
+                "browser.portal.hidden.deferKeep web=\(browserPortalDebugToken(webView)) " +
+                "reason=\(reason) frame=\(browserPortalDebugFrame(containerView.frame))"
+            )
+#endif
+            containerView.setDropZoneOverlay(zone: nil)
+            return true
+        }
         guard let anchorView = entry.anchorView, let window else {
+            if preserveVisibleDuringTransientDetach(reason: "missingAnchorOrWindow") {
+                return
+            }
             if scheduleTransientDetachRecovery(reason: "missingAnchorOrWindow") {
                 hideContainerView(reason: "missingAnchorOrWindow")
                 return
@@ -2415,21 +2436,15 @@ final class WindowBrowserPortal: NSObject {
                 anchorView.window == nil &&
                 anchorView.superview != nil
             if isOffWindowReparent {
-                let didScheduleTransientRecovery = scheduleTransientRecoveryRetryIfNeeded(
-                    forWebViewId: webViewId,
-                    entry: &entry,
-                    webView: webView,
-                    reason: "anchorWindowMismatch"
-                )
-#if DEBUG
-                if didScheduleTransientRecovery && !containerView.isHidden {
-                    dlog(
-                        "browser.portal.hidden.deferKeep web=\(browserPortalDebugToken(webView)) " +
-                        "reason=anchorWindowMismatch.offWindow frame=\(browserPortalDebugFrame(containerView.frame))"
-                    )
+                if preserveVisibleDuringTransientDetach(reason: "anchorWindowMismatch.offWindow") {
+                    return
                 }
-#endif
-                containerView.setDropZoneOverlay(zone: nil)
+                if scheduleTransientDetachRecovery(reason: "anchorWindowMismatch") {
+                    hideContainerView(reason: "anchorWindowMismatch")
+                    return
+                }
+            }
+            if preserveVisibleDuringTransientDetach(reason: "anchorWindowMismatch") {
                 return
             }
             if scheduleTransientDetachRecovery(reason: "anchorWindowMismatch") {
diff --git a/Sources/Panels/BrowserPanelView.swift b/Sources/Panels/BrowserPanelView.swift
index f7372a14..05dfaf2e 100644
--- a/Sources/Panels/BrowserPanelView.swift
+++ b/Sources/Panels/BrowserPanelView.swift
@@ -4264,6 +4264,11 @@ struct WebViewRepresentable: NSViewRepresentable {
     }
 
     private static func installPortalAnchorView(_ anchorView: NSView, in host: NSView) {
+        // SwiftUI can keep transient replacement hosts alive off-window during split
+        // reparenting. Never let those hosts steal the shared portal anchor, or the
+        // portal will bind against an anchor with no real window and WKWebView will
+        // fall into a hidden/unrendered state.
+        guard host.window != nil else { return }
         if anchorView.superview !== host {
             anchorView.removeFromSuperview()
             anchorView.frame = host.bounds
@@ -4288,13 +4293,15 @@ struct WebViewRepresentable: NSViewRepresentable {
         let paneDropContext = shouldAttachWebView ? currentPaneDropContext() : nil
         let activeSearchOverlay = shouldAttachWebView ? searchOverlay : nil
         let portalAnchorView = panel.portalAnchorView
-        Self.installPortalAnchorView(portalAnchorView, in: host)
+        if host.window != nil {
+            Self.installPortalAnchorView(portalAnchorView, in: host)
+        }
 
         host.onDidMoveToWindow = { [weak host, weak webView, weak coordinator, weak portalAnchorView] in
             guard let host, let webView, let coordinator, let portalAnchorView else { return }
             guard coordinator.attachGeneration == generation else { return }
-            Self.installPortalAnchorView(portalAnchorView, in: host)
             guard host.window != nil else { return }
+            Self.installPortalAnchorView(portalAnchorView, in: host)
             BrowserWindowPortalRegistry.bind(
                 webView: webView,
                 to: portalAnchorView,
@@ -4314,6 +4321,7 @@ struct WebViewRepresentable: NSViewRepresentable {
             guard let host, let webView, let coordinator, let portalAnchorView else { return }
             guard coordinator.attachGeneration == generation else { return }
             guard coordinator.lastPortalHostId == ObjectIdentifier(host) else { return }
+            guard host.window != nil else { return }
             Self.installPortalAnchorView(portalAnchorView, in: host)
             if host.window != nil,
                !BrowserWindowPortalRegistry.isWebView(webView, boundTo: portalAnchorView) {