Resync terminal portals after sidebar changes

Sources/Backport.swift

@@ -7,6 +7,15 @@ struct Backport<Content> {
 
 extension View {
     var backport: Backport<Self> { Backport(content: self) }
+
+    @ViewBuilder
+    func safeHelp(_ text: String) -> some View {
+        if text.isEmpty {
+            self
+        } else {
+            self.help(text)
+        }
+    }
 }
 
 extension Scene {

Sources/ContentView.swift

@@ -2591,10 +2591,14 @@ struct ContentView: View {
             if abs(sidebarState.persistedWidth - sanitized) > 0.5 {
                 sidebarState.persistedWidth = sanitized
             }
+            // Sidebar width changes are pure SwiftUI layout updates, so portal-hosted
+            // terminals need an explicit post-layout geometry resync.
+            TerminalWindowPortalRegistry.scheduleExternalGeometrySynchronizeForAllWindows()
             updateSidebarResizerBandState()
         })
 
         view = AnyView(view.onChange(of: sidebarState.isVisible) { _ in
+            TerminalWindowPortalRegistry.scheduleExternalGeometrySynchronizeForAllWindows()
             updateSidebarResizerBandState()
         })
 

Sources/TerminalWindowPortal.swift

@@ -724,7 +724,7 @@ final class WindowTerminalPortal: NSObject {
         return frameInContainer.width > 1 && frameInContainer.height > 1
     }
 
-    private func synchronizeAllEntriesFromExternalGeometryChange() {
+    fileprivate func synchronizeAllEntriesFromExternalGeometryChange() {
         guard ensureInstalled() else { return }
         synchronizeLayoutHierarchy()
         synchronizeAllHostedViews(excluding: nil)
@@ -1635,6 +1635,7 @@ final class WindowTerminalPortal: NSObject {
 enum TerminalWindowPortalRegistry {
     private static var portalsByWindowId: [ObjectIdentifier: WindowTerminalPortal] = [:]
     private static var hostedToWindowId: [ObjectIdentifier: ObjectIdentifier] = [:]
+    private static var hasPendingExternalGeometrySyncForAllWindows = false
 #if DEBUG
     private static var blockedBindCount: Int = 0
     private static var blockedBindReasons: [String: Int] = [:]
@@ -1780,6 +1781,17 @@ enum TerminalWindowPortalRegistry {
         portal.synchronizeHostedViewForAnchor(anchorView)
     }
 
+    static func scheduleExternalGeometrySynchronizeForAllWindows() {
+        guard !Self.hasPendingExternalGeometrySyncForAllWindows else { return }
+        Self.hasPendingExternalGeometrySyncForAllWindows = true
+        DispatchQueue.main.async {
+            Self.hasPendingExternalGeometrySyncForAllWindows = false
+            for portal in Self.portalsByWindowId.values {
+                portal.synchronizeAllEntriesFromExternalGeometryChange()
+            }
+        }
+    }
+
     static func hideHostedView(_ hostedView: GhosttySurfaceScrollView) {
         let hostedId = ObjectIdentifier(hostedView)
         guard let windowId = hostedToWindowId[hostedId],

cmuxTests/CmuxWebViewKeyEquivalentTests.swift

@@ -11861,6 +11861,80 @@ final class TerminalWindowPortalLifecycleTests: XCTestCase {
         portal.synchronizeHostedViewForAnchor(anchor)
         XCTAssertFalse(hosted.isHidden, "Portal should unhide after geometry is usable")
     }
+
+    func testScheduledExternalGeometrySyncRefreshesAncestorLayoutShift() {
+        let window = NSWindow(
+            contentRect: NSRect(x: 0, y: 0, width: 700, height: 420),
+            styleMask: [.titled, .closable],
+            backing: .buffered,
+            defer: false
+        )
+        defer {
+            NotificationCenter.default.post(name: NSWindow.willCloseNotification, object: window)
+            window.orderOut(nil)
+        }
+
+        realizeWindowLayout(window)
+        guard let contentView = window.contentView else {
+            XCTFail("Expected content view")
+            return
+        }
+
+        let shiftedContainer = NSView(frame: NSRect(x: 120, y: 60, width: 220, height: 160))
+        contentView.addSubview(shiftedContainer)
+        let anchor = NSView(frame: NSRect(x: 24, y: 28, width: 72, height: 56))
+        shiftedContainer.addSubview(anchor)
+
+        let surface = TerminalSurface(
+            tabId: UUID(),
+            context: GHOSTTY_SURFACE_CONTEXT_SPLIT,
+            configTemplate: nil,
+            workingDirectory: nil
+        )
+        let hosted = surface.hostedView
+        TerminalWindowPortalRegistry.bind(
+            hostedView: hosted,
+            to: anchor,
+            visibleInUI: true,
+            expectedSurfaceId: surface.id,
+            expectedGeneration: surface.portalBindingGeneration()
+        )
+        TerminalWindowPortalRegistry.synchronizeForAnchor(anchor)
+
+        let anchorCenter = NSPoint(x: anchor.bounds.midX, y: anchor.bounds.midY)
+        let originalWindowPoint = anchor.convert(anchorCenter, to: nil)
+        XCTAssertNotNil(
+            TerminalWindowPortalRegistry.terminalViewAtWindowPoint(originalWindowPoint, in: window),
+            "Initial hit-testing should resolve the portal-hosted terminal at its original window position"
+        )
+
+        shiftedContainer.frame.origin.x += 96
+        contentView.layoutSubtreeIfNeeded()
+        window.displayIfNeeded()
+
+        let shiftedWindowPoint = anchor.convert(anchorCenter, to: nil)
+        XCTAssertNotEqual(originalWindowPoint.x, shiftedWindowPoint.x, accuracy: 0.5)
+        XCTAssertNil(
+            TerminalWindowPortalRegistry.terminalViewAtWindowPoint(shiftedWindowPoint, in: window),
+            "Ancestor-only layout shifts should leave the portal stale until an external geometry sync runs"
+        )
+        XCTAssertNotNil(
+            TerminalWindowPortalRegistry.terminalViewAtWindowPoint(originalWindowPoint, in: window),
+            "Before the external geometry sync, hit-testing should still point at the stale portal location"
+        )
+
+        TerminalWindowPortalRegistry.scheduleExternalGeometrySynchronizeForAllWindows()
+        RunLoop.current.run(until: Date().addingTimeInterval(0.05))
+
+        XCTAssertNil(
+            TerminalWindowPortalRegistry.terminalViewAtWindowPoint(originalWindowPoint, in: window),
+            "The stale portal position should be cleared after the scheduled external geometry sync"
+        )
+        XCTAssertNotNil(
+            TerminalWindowPortalRegistry.terminalViewAtWindowPoint(shiftedWindowPoint, in: window),
+            "The scheduled external geometry sync should move the portal-hosted terminal to the anchor's new window position"
+        )
+    }
 }
 
 @MainActor