---
title: NSVisualEffectView.Material.underWindowBackground
framework: appkit
role: symbol
role_heading: Case
path: appkit/nsvisualeffectview/material-swift.enum/underwindowbackground
---

# NSVisualEffectView.Material.underWindowBackground

The material to show under a window’s background.

## Declaration

```swift
case underWindowBackground
```

## Discussion

Discussion Use this material on a visual effect view with a blendingMode of NSVisualEffectView.BlendingMode.behindWindow to create a sense of peeking through the back of the window. This effect creates an illusion that the background of the window has peeled away to reveal what’s under it.

## See Also

### Material Types

- [NSVisualEffectView.Material.titlebar](appkit/nsvisualeffectview/material-swift.enum/titlebar.md)
- [NSVisualEffectView.Material.selection](appkit/nsvisualeffectview/material-swift.enum/selection.md)
- [NSVisualEffectView.Material.menu](appkit/nsvisualeffectview/material-swift.enum/menu.md)
- [NSVisualEffectView.Material.popover](appkit/nsvisualeffectview/material-swift.enum/popover.md)
- [NSVisualEffectView.Material.sidebar](appkit/nsvisualeffectview/material-swift.enum/sidebar.md)
- [NSVisualEffectView.Material.headerView](appkit/nsvisualeffectview/material-swift.enum/headerview.md)
- [NSVisualEffectView.Material.sheet](appkit/nsvisualeffectview/material-swift.enum/sheet.md)
- [NSVisualEffectView.Material.windowBackground](appkit/nsvisualeffectview/material-swift.enum/windowbackground.md)
- [NSVisualEffectView.Material.hudWindow](appkit/nsvisualeffectview/material-swift.enum/hudwindow.md)
- [NSVisualEffectView.Material.fullScreenUI](appkit/nsvisualeffectview/material-swift.enum/fullscreenui.md)
- [NSVisualEffectView.Material.toolTip](appkit/nsvisualeffectview/material-swift.enum/tooltip.md)
- [NSVisualEffectView.Material.contentBackground](appkit/nsvisualeffectview/material-swift.enum/contentbackground.md)
- [NSVisualEffectView.Material.underPageBackground](appkit/nsvisualeffectview/material-swift.enum/underpagebackground.md)