diff --git a/Sources/OpenSwiftUITestsSupport/Integration/PlatformHostingControllerHelper.swift b/Sources/OpenSwiftUITestsSupport/Integration/PlatformHostingControllerHelper.swift
index 0c61fe46f..0a8b2df55 100644
--- a/Sources/OpenSwiftUITestsSupport/Integration/PlatformHostingControllerHelper.swift
+++ b/Sources/OpenSwiftUITestsSupport/Integration/PlatformHostingControllerHelper.swift
@@ -44,6 +44,10 @@ package func triggerLayoutWithWindow(
         vc.triggerLayout()
         window = vc.view.window
     }
+    #if os(macOS)
+    window.isReleasedWhenClosed = false
+    window.close()
+    #endif
     withExtendedLifetime(window) {}
 }
 
@@ -57,6 +61,10 @@ package func triggerLayoutWithWindow(
         vc.triggerLayout()
         window = vc.view.window
     }
+    #if os(macOS)
+    window.isReleasedWhenClosed = false
+    window.close()
+    #endif
     withExtendedLifetime(window) {}
 }
 
@@ -73,6 +81,10 @@ package func triggerLayoutWithWindow(
             window = vc.view.window
         }
     }
+    #if os(macOS)
+    window.isReleasedWhenClosed = false
+    window.close()
+    #endif
     withExtendedLifetime(window) {}
 }
 
@@ -89,6 +101,10 @@ package func triggerLayoutWithWindow(
             window = vc.view.window
         }
     }
+    #if os(macOS)
+    window.isReleasedWhenClosed = false
+    window.close()
+    #endif
     withExtendedLifetime(window) {}
 }
 
diff --git a/Tests/OpenSwiftUICompatibilityTests/Modifier/ViewModifier/AppearanceActionModifierCompatibilityTests.swift b/Tests/OpenSwiftUICompatibilityTests/Modifier/ViewModifier/AppearanceActionModifierCompatibilityTests.swift
index 16bf217b6..a14084603 100644
--- a/Tests/OpenSwiftUICompatibilityTests/Modifier/ViewModifier/AppearanceActionModifierCompatibilityTests.swift
+++ b/Tests/OpenSwiftUICompatibilityTests/Modifier/ViewModifier/AppearanceActionModifierCompatibilityTests.swift
@@ -7,7 +7,6 @@ import Testing
 import Foundation
 import OpenSwiftUITestsSupport
 
-@MainActor
 struct AppearanceActionModifierCompatibilityTests {
     @Test
     func appear() async throws {
@@ -70,12 +69,7 @@ struct AppearanceActionModifierCompatibilityTests {
                 )
             )
         }
-        #if os(macOS)
-        // FIXME: NSHostingView is not dealloc here
-        // See #454
-        #expect(Helper.result == "AAD")
-        #else
-        #expect(Helper.result == "AADD")
-        #endif
+        
+        await #expect(Helper.result == "AADD")
     }
 }