Fix the PaneVisible initialziation problem

dev/NavigationView/NavigationView.cpp

@@ -378,6 +378,7 @@ void NavigationView::OnApplyTemplate()
     UpdateSingleSelectionFollowsFocusTemplateSetting();
     UpdateNavigationViewUseSystemVisual();
     PropagateNavigationViewAsParent();
+    UpdatePaneVisibility();
     UpdateVisualState();
     UpdatePaneTitleMargins();
 }

dev/NavigationView/NavigationView_InteractionTests/NavigationViewTests.cs

@@ -695,6 +695,24 @@ public void ItemSourceTest()
             }
         }
 
+        [TestMethod]
+        [TestProperty("TestSuite", "A")]
+        public void VerifyPaneVisibleOnInit()
+        {
+            using (var setup = new TestSetupHelper(new[] { "NavigationView Tests", "NavigationView Init Test" }))
+            {
+                Log.Comment("Verify PaneIsVisibleItem is invisible");
+                VerifyElement.NotFound("PaneIsVisibleItem", FindBy.Name);
+
+                FindElement.ByName<Button>("ChangePaneVisible").Invoke();
+                Wait.ForIdle();
+
+                Log.Comment("Verify PaneIsVisibleItem is visible");
+                VerifyElement.Found("PaneIsVisibleItem", FindBy.Name);
+
+            }
+        }
+
         [TestMethod]
         [TestProperty("TestSuite", "A")]
         public void VerifyNavigationViewItemResponseToClickAfterBeingMovedBetweenFrames()

dev/NavigationView/TestUI/NavigationViewInitPage.xaml

@@ -26,7 +26,7 @@
                     <Button x:Name="RemoveItemButton" AutomationProperties.Name="RemoveItemButton" Content="Remove Item" Click="RemoveButton_Click"/>
                     <Button x:Name="ChangeToIEnumerableButton" AutomationProperties.Name="ChangeToIEnumerableButton" Content="Make it IEnumerable" Click="ChangeToIEnumerableButton_Clicks"/>
                     <Button x:Name="FlipOrientation" AutomationProperties.Name="FlipOrientationButton" Content="Flip Orientation" Click="FlipOrientation_Click"/>
-                
+
                     <StackPanel>
                         <Button x:Name="SwitchFrame" AutomationProperties.Name="SwitchFrame" Content="SwitchFrame" Click="SwitchFrame_Click" />
                         <TextBlock x:Name="MyLocationResult" AutomationProperties.Name="MyLocationResult" Text="Unknown"/>
@@ -53,6 +53,13 @@
                     <controls:NavigationViewItem Content="People" IsSelected="True" />
                 </controls:NavigationView.MenuItems>
             </controls:NavigationView>
+            <controls:NavigationView x:Name="NavView4"
+                IsPaneVisible="False">
+                <controls:NavigationView.MenuItems>
+                    <controls:NavigationViewItem Content="123" AutomationProperties.Name="PaneIsVisibleItem"/>
+                </controls:NavigationView.MenuItems>
+                <Button Content="Change IsPaneVisible Flag" AutomationProperties.Name="ChangePaneVisible" Click="ChangePaneVisibleButton_Click" />
+            </controls:NavigationView>
         </StackPanel>
     </Grid>
 

dev/NavigationView/TestUI/NavigationViewInitPage.xaml.cs

@@ -114,5 +114,10 @@ private void NavView2_ItemInvoked(NavigationView sender, NavigationViewItemInvok
                 MyLocationResult.Text = "Frame2";
             }
         }
+
+        private void ChangePaneVisibleButton_Click(object sender, RoutedEventArgs e)
+        {
+            NavView4.IsPaneVisible = !NavView4.IsPaneVisible;
+        }
     }
 }