---
title: UISplitViewController.SplitBehavior.overlay
framework: uikit
role: symbol
role_heading: Case
path: uikit/uisplitviewcontroller/splitbehavior-swift.enum/overlay
---

# UISplitViewController.SplitBehavior.overlay

The sidebars are layered on top of the secondary view controller, leaving the secondary view controller partially visible.

## Declaration

```swift
case overlay
```

## Discussion

Discussion This split behavior shows one or both sidebars layered on top of the secondary view controller, partially obscuring it. The secondary view controller is dimmed out, preventing interaction with its view. The possible display modes for this split behavior are: UISplitViewController.DisplayMode.secondaryOnly UISplitViewController.DisplayMode.oneOverSecondary UISplitViewController.DisplayMode.twoOverSecondary If the current display mode is not UISplitViewController.DisplayMode.twoOverSecondary and presentsWithGesture is true, the split view controller presents a special bar button item styled as a back-chevron icon. When a user taps this button, it changes the current display mode from UISplitViewController.DisplayMode.secondaryOnly to UISplitViewController.DisplayMode.oneOverSecondary, and from UISplitViewController.DisplayMode.oneOverSecondary to UISplitViewController.DisplayMode.twoOverSecondary.

## See Also

### Constants

- [UISplitViewController.SplitBehavior.automatic](uikit/uisplitviewcontroller/splitbehavior-swift.enum/automatic.md)
- [UISplitViewController.SplitBehavior.tile](uikit/uisplitviewcontroller/splitbehavior-swift.enum/tile.md)
- [UISplitViewController.SplitBehavior.displace](uikit/uisplitviewcontroller/splitbehavior-swift.enum/displace.md)