Don't change z-order of window exiting fullscreen.

When a window exits fullscreen, its child windows need to be ordered, but we shouldn't touch the z-order of the window itself as this sometimes seemed to result in the parent window being shown over the child windows. Fixes flaky integration tests (hopefully).

native/Avalonia.Native/src/OSX/WindowImpl.h

@@ -102,6 +102,7 @@ protected:
     void UpdateStyle () override;
 
 private:
+    void ZOrderChildWindows();
     void OnInitialiseNSWindow();
     NSString *_lastTitle;
 };

native/Avalonia.Native/src/OSX/WindowImpl.mm

@@ -119,14 +119,19 @@ void WindowImpl::BringToFront()
         }
         
         [Window invalidateShadow];
+        ZOrderChildWindows();
+    }
+}
+
+void WindowImpl::ZOrderChildWindows()
+{
+    for(auto iterator = _children.begin(); iterator != _children.end(); iterator++)
+    {
+        auto window = (*iterator)->Window;
         
-        for(auto iterator = _children.begin(); iterator != _children.end(); iterator++)
-        {
-            auto window = (*iterator)->Window;
-            
-            // #9565: Only bring window to front if it's on the currently active space
-            if ([window isOnActiveSpace])
-                (*iterator)->BringToFront();
+        // #9565: Only bring window to front if it's on the currently active space
+        if ([window isOnActiveSpace]) {
+            (*iterator)->BringToFront();
         }
     }
 }
@@ -154,7 +159,7 @@ void WindowImpl::EndStateTransition() {
     UpdateStyle();
 
     // Ensure correct order of child windows after fullscreen transition.
-    BringToFront();
+    ZOrderChildWindows();
 }
 
 SystemDecorations WindowImpl::Decorations() {

tests/Avalonia.IntegrationTests.Appium/WindowTests_MacOS.cs

@@ -56,7 +56,7 @@ namespace Avalonia.IntegrationTests.Appium
             }
         }
 
-        [PlatformFact(TestPlatforms.MacOS, Skip = "Flaky test, skip for now")]
+        [PlatformFact(TestPlatforms.MacOS)]
         public void WindowOrder_Modal_Dialog_Stays_InFront_Of_Parent_When_Clicking_Resize_Grip()
         {
             var mainWindow = GetWindow("MainWindow");
@@ -151,7 +151,7 @@ namespace Avalonia.IntegrationTests.Appium
             Assert.Equal("Normal", windowState.Text);
         }
 
-        [PlatformFact(TestPlatforms.MacOS, Skip = "Flaky test, skip for now")]
+        [PlatformFact(TestPlatforms.MacOS)]
         public void Does_Not_Switch_Space_From_FullScreen_To_Main_Desktop_When_FullScreen_Window_Clicked()
         {
             // Issue #9565