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# setNeedsUpdateOfVerticalBarConfiguration()

Signals to the system that the preferred vertical bar configuration,
such as its behavior, has changed.

```
func setNeedsUpdateOfVerticalBarConfiguration()
```

## Discussion

Call this method following changes to any state that affects the return
values of methods like [`preferredVerticalBarBehavior`](/documentation/UIKit/UIViewController/preferredVerticalBarBehavior) or
[`childForPreferredVerticalBarBehavior`](/documentation/UIKit/UIViewController/childForPreferredVerticalBarBehavior).

---

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