Remove code that removed focus visual in SelectionFollowsFocus mode (microsoft/microsoft-ui-xaml#3190)

Author: Kinnara

ModernWpf.Controls/NavigationView/NavigationView.cs

@@ -724,7 +724,6 @@ public override void OnApplyTemplate()
             UpdatePaneTabFocusNavigation();
             UpdateBackAndCloseButtonsVisibility();
             UpdateSingleSelectionFollowsFocusTemplateSetting();
-            UpdateNavigationViewUseSystemVisual();
             UpdatePaneVisibility();
             UpdateVisualState();
             UpdatePaneTitleMargins();
@@ -1266,11 +1265,6 @@ int init()
                     }
                     nvi.PropagateDepthToChildren(childDepth);
 
-                    if (ir != m_topNavRepeaterOverflowView)
-                    {
-                        nvibImpl.UseSystemFocusVisuals = ShouldShowFocusVisual();
-                    }
-
                     // Register for item events
                     InputHelper.AddTappedHandler(nvi, OnNavigationViewItemTapped);
                     nvi.KeyDown += OnNavigationViewItemKeyDown;
@@ -3372,45 +3366,6 @@ void UpdateLeftNavigationOnlyVisualState(bool useTransitions)
             VisualStateManager.GoToState(this, isToggleButtonVisible ? "TogglePaneButtonVisible" : "TogglePaneButtonCollapsed", false /*useTransitions*/);
         }
 
-        void UpdateNavigationViewUseSystemVisual()
-        {
-            if (SharedHelpers.IsRS1OrHigher() && !ShouldPreserveNavigationViewRS4Behavior() && m_appliedTemplate)
-            {
-                PropagateShowFocusVisualToAllNavigationViewItemsInRepeater(m_leftNavRepeater, ShouldShowFocusVisual());
-                PropagateShowFocusVisualToAllNavigationViewItemsInRepeater(m_leftNavFooterMenuRepeater, ShouldShowFocusVisual());
-                PropagateShowFocusVisualToAllNavigationViewItemsInRepeater(m_topNavRepeater, ShouldShowFocusVisual());
-                PropagateShowFocusVisualToAllNavigationViewItemsInRepeater(m_topNavFooterMenuRepeater, ShouldShowFocusVisual());
-            }
-        }
-
-        bool ShouldShowFocusVisual()
-        {
-            return SelectionFollowsFocus == NavigationViewSelectionFollowsFocus.Disabled;
-        }
-
-        void PropagateShowFocusVisualToAllNavigationViewItemsInRepeater(ItemsRepeater ir, bool showFocusVisual)
-        {
-            if (ir != null)
-            {
-                if (ir.ItemsSourceView is { } itemsSourceView)
-                {
-                    var numberOfItems = itemsSourceView.Count;
-                    for (int i = 0; i < numberOfItems; i++)
-                    {
-                        if (ir.TryGetElement(i) is { } nvib)
-                        {
-                            if (nvib is NavigationViewItem nvi)
-                            {
-                                var nviImpl = nvi;
-                                nviImpl.UseSystemFocusVisuals = showFocusVisual;
-                            }
-                        }
-
-                    }
-                }
-            }
-        }
-
         void InvalidateTopNavPrimaryLayout()
         {
             if (m_appliedTemplate && IsTopNavigationView())
@@ -4007,7 +3962,6 @@ void PropertyChanged(DependencyPropertyChangedEventArgs args)
             else if (property == SelectionFollowsFocusProperty)
             {
                 UpdateSingleSelectionFollowsFocusTemplateSetting();
-                UpdateNavigationViewUseSystemVisual();
             }
             else if (property == IsPaneToggleButtonVisibleProperty)
             {

ModernWpf.Controls/NavigationView/NavigationView.xaml

@@ -1377,10 +1377,6 @@
         </Setter>
     </Style>
 
-    <!--Note: Even though UseSystemFocusVisuals is set to True here in the Style, and because
-    bindings in Styles are only evaluated once, we were unable to bring a TemplateSettings.UseSystemFocusVisuals
-    to handle the removal of the focus rect when SelectionFollowsFocus is enabled. Therefore, that has
-    been done in code and it's updated whenever SelectionFollowsFocus is changed.-->
     <Style TargetType="local:NavigationViewItem">
         <Setter Property="Foreground" Value="{DynamicResource NavigationViewItemForeground}" />
         <Setter Property="Background" Value="{DynamicResource NavigationViewItemBackground}" />