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# supportsMultipleWindows

A Boolean value that indicates whether the current platform supports
opening multiple windows.

```
var supportsMultipleWindows: Bool { get }
```

## Discussion

Read this property from the environment to determine if your app can
use the [`openWindow`](/documentation/SwiftUI/EnvironmentValues/openWindow) action to open new windows:

```
struct NewMailViewerButton: View {
    @Environment(\.supportsMultipleWindows) private var supportsMultipleWindows
    @Environment(\.openWindow) private var openWindow

    var body: some View {
        Button("Open New Window") {
            openWindow(id: "mail-viewer")
        }
        .disabled(!supportsMultipleWindows)
    }
}
```

The reported value depends on both the platform and how you configure
your app:

- In macOS, this property returns `true` for any app that uses the
  SwiftUI app lifecycle.
- In iPadOS, this property returns `true` for any app that uses the
  SwiftUI app lifecycle and has the Information Property List key
  <doc://com.apple.documentation/documentation/BundleResources/Information-Property-List/UIApplicationSceneManifest/UIApplicationSupportsMultipleScenes> set to `true`.
- For all other platforms and configurations, the value returns `false`.

If the value is false and you try to open a window, SwiftUI
ignores the action and logs a runtime error.

---

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