Merge pull request #1215 from manaflow-ai/issue-1208-browser-pane-stale-content

Fix stale browser pane content after drag splits

Sources/BrowserWindowPortal.swift

@@ -2851,9 +2851,12 @@ final class WindowBrowserPortal: NSObject {
             }
             return
         }
+        let previousTransientRecoveryReason = entry.transientRecoveryReason
         func hideContainerView(reason: String) {
             containerView.setPaneTopChromeHeight(0)
             containerView.setSearchOverlay(nil)
+            containerView.setPaneDropContext(nil)
+            containerView.setPortalDragDropZone(nil)
             containerView.setDropZoneOverlay(zone: nil)
             if !containerView.isHidden, webView.superview === containerView {
                 webView.browserPortalNotifyHidden(reason: reason)
@@ -2884,6 +2887,8 @@ final class WindowBrowserPortal: NSObject {
                 "reason=\(reason) frame=\(browserPortalDebugFrame(containerView.frame))"
             )
 #endif
+            containerView.setPaneDropContext(nil)
+            containerView.setPortalDragDropZone(nil)
             containerView.setDropZoneOverlay(zone: nil)
             return true
         }
@@ -3027,6 +3032,9 @@ final class WindowBrowserPortal: NSObject {
                         "reason=hostBoundsNotReady frame=\(browserPortalDebugFrame(containerView.frame))"
                     )
 #endif
+                    containerView.setPaneDropContext(nil)
+                    containerView.setPortalDragDropZone(nil)
+                    containerView.setDropZoneOverlay(zone: nil)
                     return
                 }
             } else {
@@ -3089,6 +3097,10 @@ final class WindowBrowserPortal: NSObject {
             shouldHide &&
             entry.visibleInUI &&
             !containerView.isHidden
+        let recoveredFromTransientGeometry =
+            previousTransientRecoveryReason != nil &&
+            transientRecoveryReason == nil &&
+            !shouldHide
 #if DEBUG
         let frameWasClamped = hasFiniteFrame && !Self.rectApproximatelyEqual(frameInHost, targetFrame)
         if frameWasClamped {
@@ -3131,6 +3143,7 @@ final class WindowBrowserPortal: NSObject {
             if hasExistingVisibleFrame {
                 containerView.setDropZoneOverlay(zone: nil)
                 containerView.setPaneDropContext(nil)
+                containerView.setPortalDragDropZone(nil)
                 return
             }
         }
@@ -3240,10 +3253,16 @@ final class WindowBrowserPortal: NSObject {
         }
         containerView.setPaneTopChromeHeight(shouldHide ? 0 : entry.paneTopChromeHeight)
         containerView.setSearchOverlay(shouldHide ? nil : entry.searchOverlay)
+        containerView.setPaneDropContext(containerView.isHidden ? nil : entry.paneDropContext)
         containerView.setDropZoneOverlay(zone: containerView.isHidden ? nil : entry.dropZone)
         if revealedForDisplay {
             refreshReasons.append("reveal")
         }
+        if recoveredFromTransientGeometry {
+            // Drag/reparent churn can recover to the same visible frame we preserved.
+            // Force a redraw so WebKit doesn't keep stale tiles until a later resize/focus.
+            refreshReasons.append("transientRecovery")
+        }
         if forcePresentationRefresh {
             refreshReasons.append("anchor")
         }
@@ -3254,7 +3273,7 @@ final class WindowBrowserPortal: NSObject {
             containerOwnsWebView &&
             hostView.reapplyHostedInspectorDividerIfNeeded(in: containerView, reason: "portal.sync")
         if !shouldHide, containerOwnsWebView, !refreshReasons.isEmpty {
-            if hostedInspectorAdjustedDuringSync {
+            if hostedInspectorAdjustedDuringSync && !recoveredFromTransientGeometry {
 #if DEBUG
                 dlog(
                     "browser.portal.refresh.skip web=\(browserPortalDebugToken(webView)) " +

Sources/Panels/BrowserPanel.swift

@@ -2005,6 +2005,12 @@ final class BrowserPanel: Panel, ObservableObject {
         setupObservers(for: webView)
     }
 
+    private func isCurrentWebView(_ candidate: WKWebView, instanceID: UUID? = nil) -> Bool {
+        guard candidate === webView else { return false }
+        guard let instanceID else { return true }
+        return instanceID == webViewInstanceID
+    }
+
     init(workspaceId: UUID, initialURL: URL? = nil, bypassInsecureHTTPHostOnce: String? = nil) {
         self.id = UUID()
         self.workspaceId = workspaceId
@@ -2020,15 +2026,16 @@ final class BrowserPanel: Panel, ObservableObject {
         navDelegate.didFinish = { webView in
             BrowserHistoryStore.shared.recordVisit(url: webView.url, title: webView.title)
             Task { @MainActor [weak self] in
-                self?.refreshFavicon(from: webView)
-                self?.applyBrowserThemeModeIfNeeded()
+                guard let self, self.isCurrentWebView(webView) else { return }
+                self.refreshFavicon(from: webView)
+                self.applyBrowserThemeModeIfNeeded()
                 // Keep find-in-page open through load completion and refresh matches for the new DOM.
-                self?.restoreFindStateAfterNavigation(replaySearch: true)
+                self.restoreFindStateAfterNavigation(replaySearch: true)
             }
         }
-        navDelegate.didFailNavigation = { [weak self] _, failedURL in
+        navDelegate.didFailNavigation = { [weak self] failedWebView, failedURL in
             Task { @MainActor in
-                guard let self else { return }
+                guard let self, self.isCurrentWebView(failedWebView) else { return }
                 // Clear stale title/favicon from the previous page so the tab
                 // shows the failed URL instead of the old page's branding.
                 self.pageTitle = failedURL.isEmpty ? "" : failedURL
@@ -2162,10 +2169,13 @@ final class BrowserPanel: Panel, ObservableObject {
     }
 
     private func setupObservers(for webView: WKWebView) {
+        let observedWebViewInstanceID = webViewInstanceID
+
         // URL changes
         let urlObserver = webView.observe(\.url, options: [.new]) { [weak self] webView, _ in
             Task { @MainActor in
-                self?.currentURL = webView.url
+                guard let self, self.isCurrentWebView(webView, instanceID: observedWebViewInstanceID) else { return }
+                self.currentURL = webView.url
             }
         }
         webViewObservers.append(urlObserver)
@@ -2173,12 +2183,13 @@ final class BrowserPanel: Panel, ObservableObject {
         // Title changes
         let titleObserver = webView.observe(\.title, options: [.new]) { [weak self] webView, _ in
             Task { @MainActor in
+                guard let self, self.isCurrentWebView(webView, instanceID: observedWebViewInstanceID) else { return }
                 // Keep showing the last non-empty title while the new navigation is loading.
                 // WebKit often clears title to nil/"" during reload/navigation, which causes
                 // a distracting tab-title flash (e.g. to host/URL). Only accept non-empty titles.
                 let trimmed = (webView.title ?? "").trimmingCharacters(in: .whitespacesAndNewlines)
                 guard !trimmed.isEmpty else { return }
-                self?.pageTitle = trimmed
+                self.pageTitle = trimmed
             }
         }
         webViewObservers.append(titleObserver)
@@ -2186,7 +2197,8 @@ final class BrowserPanel: Panel, ObservableObject {
         // Loading state
         let loadingObserver = webView.observe(\.isLoading, options: [.new]) { [weak self] webView, _ in
             Task { @MainActor in
-                self?.handleWebViewLoadingChanged(webView.isLoading)
+                guard let self, self.isCurrentWebView(webView, instanceID: observedWebViewInstanceID) else { return }
+                self.handleWebViewLoadingChanged(webView.isLoading)
             }
         }
         webViewObservers.append(loadingObserver)
@@ -2194,7 +2206,7 @@ final class BrowserPanel: Panel, ObservableObject {
         // Can go back
         let backObserver = webView.observe(\.canGoBack, options: [.new]) { [weak self] webView, _ in
             Task { @MainActor in
-                guard let self else { return }
+                guard let self, self.isCurrentWebView(webView, instanceID: observedWebViewInstanceID) else { return }
                 self.nativeCanGoBack = webView.canGoBack
                 self.refreshNavigationAvailability()
             }
@@ -2204,7 +2216,7 @@ final class BrowserPanel: Panel, ObservableObject {
         // Can go forward
         let forwardObserver = webView.observe(\.canGoForward, options: [.new]) { [weak self] webView, _ in
             Task { @MainActor in
-                guard let self else { return }
+                guard let self, self.isCurrentWebView(webView, instanceID: observedWebViewInstanceID) else { return }
                 self.nativeCanGoForward = webView.canGoForward
                 self.refreshNavigationAvailability()
             }
@@ -2214,7 +2226,8 @@ final class BrowserPanel: Panel, ObservableObject {
         // Progress
         let progressObserver = webView.observe(\.estimatedProgress, options: [.new]) { [weak self] webView, _ in
             Task { @MainActor in
-                self?.estimatedProgress = webView.estimatedProgress
+                guard let self, self.isCurrentWebView(webView, instanceID: observedWebViewInstanceID) else { return }
+                self.estimatedProgress = webView.estimatedProgress
             }
         }
         webViewObservers.append(progressObserver)
@@ -2250,6 +2263,9 @@ final class BrowserPanel: Panel, ObservableObject {
 
         webViewObservers.removeAll()
         webViewCancellables.removeAll()
+        faviconTask?.cancel()
+        faviconTask = nil
+        faviconRefreshGeneration &+= 1
         BrowserWindowPortalRegistry.detach(webView: terminatedWebView)
         terminatedWebView.stopLoading()
         terminatedWebView.navigationDelegate = nil
@@ -2260,11 +2276,12 @@ final class BrowserPanel: Panel, ObservableObject {
 
         let replacement = Self.makeWebView()
         replacement.pageZoom = desiredZoom
-        webView = replacement
         webViewInstanceID = UUID()
+        webView = replacement
         shouldRenderWebView = wasRenderable
 
         bindWebView(replacement)
+        applyBrowserThemeModeIfNeeded()
 
         if !history.backHistoryURLStrings.isEmpty || !history.forwardHistoryURLStrings.isEmpty {
             restoreSessionNavigationHistory(
@@ -2360,9 +2377,11 @@ final class BrowserPanel: Panel, ObservableObject {
         guard let scheme = pageURL.scheme?.lowercased(), scheme == "http" || scheme == "https" else { return }
         faviconRefreshGeneration &+= 1
         let refreshGeneration = faviconRefreshGeneration
+        let refreshWebViewInstanceID = webViewInstanceID
 
         faviconTask = Task { @MainActor [weak self, weak webView] in
             guard let self, let webView else { return }
+            guard self.isCurrentWebView(webView, instanceID: refreshWebViewInstanceID) else { return }
             guard self.isCurrentFaviconRefresh(generation: refreshGeneration) else { return }
 
             // Try to discover the best icon URL from the document.
@@ -2397,6 +2416,7 @@ final class BrowserPanel: Panel, ObservableObject {
                     discoveredURL = u
                 }
             }
+            guard self.isCurrentWebView(webView, instanceID: refreshWebViewInstanceID) else { return }
             guard self.isCurrentFaviconRefresh(generation: refreshGeneration) else { return }
 
             let fallbackURL = URL(string: "/favicon.ico", relativeTo: pageURL)
@@ -2422,6 +2442,7 @@ final class BrowserPanel: Panel, ObservableObject {
             } catch {
                 return
             }
+            guard self.isCurrentWebView(webView, instanceID: refreshWebViewInstanceID) else { return }
             guard self.isCurrentFaviconRefresh(generation: refreshGeneration) else { return }
 
             guard let http = response as? HTTPURLResponse,
@@ -2701,12 +2722,121 @@ final class BrowserPanel: Panel, ObservableObject {
         if let detachedDeveloperToolsWindowCloseObserver {
             NotificationCenter.default.removeObserver(detachedDeveloperToolsWindowCloseObserver)
         }
+        webViewObservers.removeAll()
+        webViewCancellables.removeAll()
         let webView = webView
         Task { @MainActor in
             BrowserWindowPortalRegistry.detach(webView: webView)
         }
+    }
+}
+
+extension BrowserPanel {
+    private var needsWorkspaceContextReset: Bool {
+        shouldRenderWebView ||
+        currentURL != nil ||
+        !pageTitle.isEmpty ||
+        faviconPNGData != nil ||
+        searchState != nil ||
+        nativeCanGoBack ||
+        nativeCanGoForward ||
+        restoredHistoryCurrentURL != nil ||
+        !restoredBackHistoryStack.isEmpty ||
+        !restoredForwardHistoryStack.isEmpty ||
+        estimatedProgress > 0 ||
+        isLoading ||
+        isDownloading ||
+        activeDownloadCount != 0 ||
+        preferredDeveloperToolsVisible ||
+        webView.superview != nil
+    }
+
+    func resetForWorkspaceContextChange(reason: String) {
+        guard needsWorkspaceContextReset else {
+#if DEBUG
+            dlog(
+                "browser.contextReset.skip panel=\(id.uuidString.prefix(5)) " +
+                "reason=\(reason) render=\(shouldRenderWebView ? 1 : 0)"
+            )
+#endif
+            return
+        }
+
+#if DEBUG
+        dlog(
+            "browser.contextReset.begin panel=\(id.uuidString.prefix(5)) " +
+            "reason=\(reason) render=\(shouldRenderWebView ? 1 : 0) " +
+            "url=\(preferredURLStringForOmnibar() ?? "nil")"
+        )
+#endif
+
+        _ = hideDeveloperTools()
+        cancelDeveloperToolsRestoreRetry()
+        preferredDeveloperToolsVisible = false
+        preferredDeveloperToolsPresentation = .unknown
+        forceDeveloperToolsRefreshOnNextAttach = false
+        developerToolsDetachedOpenGraceDeadline = nil
+        developerToolsRestoreRetryAttempt = 0
+        preferredAttachedDeveloperToolsWidth = nil
+        preferredAttachedDeveloperToolsWidthFraction = nil
+
+        loadingEndWorkItem?.cancel()
+        loadingEndWorkItem = nil
+        faviconTask?.cancel()
+        faviconTask = nil
+        faviconRefreshGeneration &+= 1
+        loadingGeneration &+= 1
+        activeDownloadCount = 0
+        isDownloading = false
+        isLoading = false
+        estimatedProgress = 0
+        nativeCanGoBack = false
+        nativeCanGoForward = false
+        navigationDelegate?.lastAttemptedURL = nil
+        abandonRestoredSessionHistoryIfNeeded()
+
+        pendingAddressBarFocusRequestId = nil
+        preferredFocusIntent = .addressBar
+        suppressOmnibarAutofocusUntil = nil
+        suppressWebViewFocusUntil = nil
+        endSuppressWebViewFocusForAddressBar()
+        invalidateAddressBarPageFocusRestoreAttempts()
+        invalidateSearchFocusRequests(reason: "contextReset")
+        searchState = nil
+
+        pageTitle = ""
+        currentURL = nil
+        faviconPNGData = nil
+        lastFaviconURLString = nil
+        activePortalHostLease = nil
+        pendingDistinctPortalHostReplacementPaneId = nil
+        lockedPortalHost = nil
+
+        let oldWebView = webView
         webViewObservers.removeAll()
         webViewCancellables.removeAll()
+        BrowserWindowPortalRegistry.detach(webView: oldWebView)
+        oldWebView.stopLoading()
+        oldWebView.navigationDelegate = nil
+        oldWebView.uiDelegate = nil
+        if let oldCmuxWebView = oldWebView as? CmuxWebView {
+            oldCmuxWebView.onContextMenuDownloadStateChanged = nil
+        }
+
+        let replacement = Self.makeWebView()
+        webViewInstanceID = UUID()
+        webView = replacement
+        shouldRenderWebView = false
+        bindWebView(replacement)
+        applyBrowserThemeModeIfNeeded()
+        refreshNavigationAvailability()
+
+#if DEBUG
+        dlog(
+            "browser.contextReset.end panel=\(id.uuidString.prefix(5)) " +
+            "reason=\(reason) instance=\(webViewInstanceID.uuidString.prefix(6))"
+        )
+#endif
     }
 }
 

Sources/Panels/BrowserPanelView.swift

@@ -5523,12 +5523,11 @@ struct WebViewRepresentable: NSViewRepresentable {
         }
 
         // SwiftUI can transiently dismantle/rebuild the browser host view during split
-        // rearrangement. Do not detach the portal-hosted WKWebView here; explicit detach
-        // still happens on real web view replacement and panel teardown.
+        // rearrangement. Do not detach the portal-hosted WKWebView or clear its pane-drop
+        // context here; explicit teardown still happens on real web view replacement and
+        // panel teardown, and preserving this state lets internal tab drags re-enter the
+        // browser pane while SwiftUI churns underneath.
         BrowserWindowPortalRegistry.updateDropZoneOverlay(for: webView, zone: nil)
-        BrowserWindowPortalRegistry.updatePaneTopChromeHeight(for: webView, height: 0)
-        BrowserWindowPortalRegistry.updatePaneDropContext(for: webView, context: nil)
-        BrowserWindowPortalRegistry.updateSearchOverlay(for: webView, configuration: nil)
         coordinator.lastPortalHostId = nil
         coordinator.lastSynchronizedHostGeometryRevision = 0
     }

Sources/TerminalController.swift

@@ -13813,16 +13813,7 @@ class TerminalController {
                 result = "ERROR: Tab not found"
                 return
             }
-            tab.statusEntries.removeAll()
-            tab.logEntries.removeAll()
-            tab.progress = nil
-            tab.gitBranch = nil
-            tab.panelGitBranches.removeAll()
-            tab.pullRequest = nil
-            tab.panelPullRequests.removeAll()
-            tab.surfaceListeningPorts.removeAll()
-            tab.listeningPorts.removeAll()
-            tab.metadataBlocks.removeAll()
+            tab.resetSidebarContext(reason: "reset_sidebar")
         }
         return result
     }

Sources/Workspace.swift

@@ -1686,6 +1686,57 @@ final class Workspace: Identifiable, ObservableObject {
         }
     }
 
+    func resetSidebarContext(reason: String = "unspecified") {
+        statusEntries.removeAll()
+        logEntries.removeAll()
+        progress = nil
+        gitBranch = nil
+        panelGitBranches.removeAll()
+        pullRequest = nil
+        panelPullRequests.removeAll()
+        surfaceListeningPorts.removeAll()
+        listeningPorts.removeAll()
+        metadataBlocks.removeAll()
+        resetBrowserPanelsForContextChange(reason: reason)
+    }
+
+    func resetBrowserPanelsForContextChange(reason: String) {
+        let browserPanels = panels.values.compactMap { $0 as? BrowserPanel }
+        guard !browserPanels.isEmpty else { return }
+
+#if DEBUG
+        dlog(
+            "workspace.contextReset.browserPanels workspace=\(id.uuidString.prefix(5)) " +
+            "reason=\(reason) count=\(browserPanels.count)"
+        )
+#endif
+
+        for browserPanel in browserPanels {
+            browserPanel.resetForWorkspaceContextChange(reason: reason)
+            let nextTitle = browserPanel.displayTitle
+            _ = updatePanelTitle(panelId: browserPanel.id, title: nextTitle)
+
+            guard let tabId = surfaceIdFromPanelId(browserPanel.id),
+                  let existing = bonsplitController.tab(tabId) else {
+                continue
+            }
+
+            let faviconUpdate: Data?? = existing.iconImageData == nil ? nil : .some(nil)
+            let loadingUpdate: Bool? = existing.isLoading ? false : nil
+
+            guard faviconUpdate != nil || loadingUpdate != nil else {
+                continue
+            }
+
+            bonsplitController.updateTab(
+                tabId,
+                iconImageData: faviconUpdate,
+                hasCustomTitle: panelCustomTitles[browserPanel.id] != nil,
+                isLoading: loadingUpdate
+            )
+        }
+    }
+
     @discardableResult
     func updatePanelTitle(panelId: UUID, title: String) -> Bool {
         let trimmed = title.trimmingCharacters(in: .whitespacesAndNewlines)
@@ -4839,6 +4890,21 @@ extension Workspace: BonsplitDelegate {
             "originalKinds=[\(paneKindSummary(originalPane))] newKinds=[\(paneKindSummary(newPane))]"
         )
 #endif
+        let rearmBrowserPortalHostReplacement: (PaneID, String) -> Void = { paneId, reason in
+            for tab in controller.tabs(inPane: paneId) {
+                guard let panelId = self.panelIdFromSurfaceId(tab.id),
+                      let browserPanel = self.browserPanel(for: panelId) else {
+                    continue
+                }
+                browserPanel.preparePortalHostReplacementForNextDistinctClaim(
+                    inPane: paneId,
+                    reason: reason
+                )
+            }
+        }
+        rearmBrowserPortalHostReplacement(originalPane, "workspace.didSplit.original")
+        rearmBrowserPortalHostReplacement(newPane, "workspace.didSplit.new")
+
         // Only auto-create a terminal if the split came from bonsplit UI.
         // Programmatic splits via newTerminalSplit() set isProgrammaticSplit and handle their own panels.
         guard !isProgrammaticSplit else {

cmuxTests/CmuxWebViewKeyEquivalentTests.swift

@@ -2430,6 +2430,89 @@ final class BrowserSessionHistoryRestoreTests: XCTestCase {
 
         XCTAssertFalse(panel.shouldRenderWebView)
     }
+
+    func testResetSidebarContextClearsBrowserPanelsIntoNewTabState() throws {
+        let workspace = Workspace()
+        let paneId = try XCTUnwrap(workspace.bonsplitController.allPaneIds.first)
+        let contextPanelId = try XCTUnwrap(workspace.focusedPanelId)
+        let browser = try XCTUnwrap(
+            workspace.newBrowserSurface(
+                inPane: paneId,
+                url: URL(string: "https://example.com"),
+                focus: false
+            )
+        )
+
+        browser.restoreSessionNavigationHistory(
+            backHistoryURLStrings: ["https://example.com/prev"],
+            forwardHistoryURLStrings: ["https://example.com/next"],
+            currentURLString: "https://example.com/current"
+        )
+        browser.startFind()
+
+        workspace.statusEntries["task"] = SidebarStatusEntry(key: "task", value: "Issue #1208")
+        workspace.metadataBlocks["notes"] = SidebarMetadataBlock(
+            key: "notes",
+            markdown: "test",
+            priority: 0,
+            timestamp: Date()
+        )
+        workspace.progress = SidebarProgressState(value: 0.5, label: "Loading")
+        workspace.updatePanelGitBranch(panelId: contextPanelId, branch: "issue-1208", isDirty: false)
+        workspace.updatePanelPullRequest(
+            panelId: contextPanelId,
+            number: 1208,
+            label: "PR",
+            url: try XCTUnwrap(URL(string: "https://example.com/pull/1208")),
+            status: .open
+        )
+        workspace.logEntries.append(
+            SidebarLogEntry(
+                message: "Issue #1208",
+                level: .info,
+                source: "test",
+                timestamp: Date()
+            )
+        )
+        workspace.surfaceListeningPorts[contextPanelId] = [3000]
+        workspace.recomputeListeningPorts()
+
+        XCTAssertTrue(browser.shouldRenderWebView)
+        XCTAssertNotNil(browser.preferredURLStringForOmnibar())
+        XCTAssertTrue(browser.canGoBack)
+        XCTAssertTrue(browser.canGoForward)
+        XCTAssertNotNil(browser.searchState)
+        XCTAssertFalse(workspace.statusEntries.isEmpty)
+        XCTAssertFalse(workspace.logEntries.isEmpty)
+        XCTAssertFalse(workspace.metadataBlocks.isEmpty)
+        XCTAssertNotNil(workspace.progress)
+        XCTAssertNotNil(workspace.gitBranch)
+        XCTAssertNotNil(workspace.pullRequest)
+        XCTAssertEqual(workspace.listeningPorts, [3000])
+
+        let priorWebView = browser.webView
+        let priorInstanceID = browser.webViewInstanceID
+        workspace.resetSidebarContext(reason: "test")
+
+        XCTAssertTrue(workspace.statusEntries.isEmpty)
+        XCTAssertTrue(workspace.logEntries.isEmpty)
+        XCTAssertTrue(workspace.metadataBlocks.isEmpty)
+        XCTAssertNil(workspace.progress)
+        XCTAssertNil(workspace.gitBranch)
+        XCTAssertTrue(workspace.panelGitBranches.isEmpty)
+        XCTAssertNil(workspace.pullRequest)
+        XCTAssertTrue(workspace.panelPullRequests.isEmpty)
+        XCTAssertTrue(workspace.surfaceListeningPorts.isEmpty)
+        XCTAssertTrue(workspace.listeningPorts.isEmpty)
+        XCTAssertFalse(browser.shouldRenderWebView)
+        XCTAssertNil(browser.preferredURLStringForOmnibar())
+        XCTAssertFalse(browser.canGoBack)
+        XCTAssertFalse(browser.canGoForward)
+        XCTAssertNil(browser.searchState)
+        XCTAssertFalse(browser.webView === priorWebView)
+        XCTAssertNotEqual(browser.webViewInstanceID, priorInstanceID)
+    }
+
 }
 
 @MainActor