NavigationView: refresh closed compact state when a reused NavigationViewItem is loaded in a new host

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: ec9a38b2-2629-4a10-bfb5-552decfe6848

controls/dev/NavigationView/NavigationViewItem.cpp

@@ -42,6 +42,10 @@ NavigationViewItem::NavigationViewItem()
 {
     SetDefaultStyleKey(this);
     SetValue(s_MenuItemsProperty, winrt::make<Vector<winrt::IInspectable>>());
+
+    // Items outside a NavigationView-owned repeater are only prepared on load (see OnLoaded), and they can be
+    // moved to a different host later (for example from MenuItems to PaneFooter or Content).
+    Loaded({ this, &NavigationViewItem::OnLoaded });
 }
 
 void NavigationViewItem::UpdateVisualStateNoTransition()
@@ -101,12 +105,6 @@ void NavigationViewItem::OnApplyTemplate()
     {
         PrepNavigationViewItem(splitView);
     }
-    else
-    {
-        // If the NVI is not prepared in an ItemPresenter, it will not have reference to SplitView. So check OnLoaded
-        // if it the reference has been manually set in NavigationViewItemBase::OnLoaded(). 
-        Loaded({ this, &NavigationViewItem::OnLoaded });
-    }
 
     if (HasPotentialChildren())
     {
@@ -175,6 +173,15 @@ void NavigationViewItem::LoadMenuItemsHost()
 
 void NavigationViewItem::OnLoaded(winrt::IInspectable const&, winrt::RoutedEventArgs const&)
 {
+    // Items in a NavigationView-owned repeater are prepared in OnApplyTemplate and refreshed by the repeater.
+    if (IsInNavigationViewOwnedRepeater() && m_splitViewIsPaneOpenChangedRevoker)
+    {
+        return;
+    }
+
+    // If the NVI is not prepared in an ItemPresenter, it will not have reference to SplitView, so it is prepared here once
+    // NavigationViewItemBase::OnLoaded() has set the NavigationView. This also runs again when the item is loaded in a new host,
+    // so the closed compact state is recomputed for that host. Re-preparing replaces the SplitView subscriptions.
     if (auto splitView = GetSplitView())
     {
         PrepNavigationViewItem(splitView);