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# pageControllerWillStartLiveTransition(_:)

This message is sent when the user begins a transition.

```
@MainActor optional func pageControllerWillStartLiveTransition(_ pageController: NSPageController)
```

## Parameters

`pageController`

The page controller.

## Discussion

This message is sent when the user begins a transition whether via a swipe gesture of one of the page controller’s target-action navigation methods.

---

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