Keep the checklist popover when a row reparent's close finishes after reattach

Sources/Sidebar/AppKitList/Cells/SidebarRowSwiftUIPopoverPresenter.swift

@@ -41,6 +41,11 @@ final class SidebarRowSwiftUIPopoverPresenter: NSObject, NSPopoverDelegate {
 
     var isShown: Bool { popover?.isShown == true }
 
+    /// True from `popoverWillClose` until `popoverDidClose`. An animated close
+    /// keeps `isShown` true until the animation ends, so containers that
+    /// must know whether a close already began check this as well.
+    private(set) var isClosing = false
+
     func present(
         _ root: AnyView,
         relativeTo rect: NSRect,
@@ -112,7 +117,12 @@ final class SidebarRowSwiftUIPopoverPresenter: NSObject, NSPopoverDelegate {
         PopoverKeyWindowElevator.promoteToKeyIfPossible(hostingController.view.window)
     }
 
+    func popoverWillClose(_ notification: Notification) {
+        isClosing = true
+    }
+
     func popoverDidClose(_ notification: Notification) {
+        isClosing = false
         visibleUpdateScheduler.cancel()
         pendingRoot = nil
         popover = nil

Sources/Sidebar/AppKitList/Cells/SidebarWorkspaceRowChecklistSection.swift

@@ -493,10 +493,21 @@ final class SidebarRowChecklistSection: NSView {
 
     override func viewDidMoveToWindow() {
         super.viewDidMoveToWindow()
-        if window != nil, popoverPresenter.isShown {
-            // The popover survived the reparent, so a later close is a real
-            // click-away rather than a detach side effect.
-            popoverAnchorDetachedWhilePresented = false
+        if window != nil, popoverAnchorDetachedWhilePresented, popoverPresenter.isShown {
+            // The popover may have survived the reparent, in which case a
+            // later close is a real click-away rather than a detach side
+            // effect. Decide once the reattach settles: an animated popover
+            // stays `isShown` while its detach-induced close animates, and
+            // that close can finish after the anchor is back in the window.
+            let generation = popoverPresentationGeneration
+            DispatchQueue.main.async { [weak self] in
+                guard let self,
+                      self.popoverPresentationGeneration == generation,
+                      self.window != nil,
+                      self.popoverPresenter.isShown,
+                      !self.popoverPresenter.isClosing else { return }
+                self.popoverAnchorDetachedWhilePresented = false
+            }
         }
         if window != nil, pendingPopoverPresentation {
             needsLayout = true