---
title: auxiliary
framework: appkit
role: symbol
role_heading: Type Property
path: appkit/nswindow/collectionbehavior-swift.struct/auxiliary
---

# auxiliary

The behavior marking this window as auxiliary for both Stage Manager and full screen.

## Declaration

```swift
static var auxiliary: NSWindow.CollectionBehavior { get }
```

## Discussion

Discussion Marking a window collection behavior as auxiliary means it becomes auxiliary for both Stage Manager and full screen display modes. Auxiliary windows prefer being shown alongside primary windows. To set a different behavior in full screen, while keeping Stage Manager auxiliary, set a more specific behavior just for full screen mode (see fullScreenNone). Use this collection behavior for About or Settings windows as well as utility panes. note: This property is mutually exclusive. Set only one of primary, auxiliary, or canJoinAllApplications on a window handled by Stage Manager at a time.

## See Also

### Stage Manager and full screen

- [primary](appkit/nswindow/collectionbehavior-swift.struct/primary.md)
- [canJoinAllApplications](appkit/nswindow/collectionbehavior-swift.struct/canjoinallapplications.md)