<!--
{
  "availability" : [
    "macCatalyst: -",
    "macOS: 10.0.0 - 10.12.0"
  ],
  "documentType" : "symbol",
  "framework" : "AppKit",
  "identifier" : "/documentation/AppKit/NSHUDWindowMask",
  "metadataVersion" : "0.1.0",
  "role" : "Global Variable",
  "symbol" : {
    "kind" : "Global Variable",
    "modules" : [
      "AppKit"
    ],
    "preciseIdentifier" : "c:@NSHUDWindowMask"
  },
  "title" : "NSHUDWindowMask"
}
-->

# NSHUDWindowMask

The panel is created as a transparent panel (sometimes called a “heads-up display”).

```
static const NSWindowStyleMask NSHUDWindowMask;
```

## Discussion

Valid only for an instance of `NSPanel` or its subclasses; not valid for a window.

Using the C bitwise OR operator, `NSHUDWindowMask` can be combined with other style masks (some of which are documented in Window Style Masks) with the following results:

- `NSBorderlessWindowMask`: Borderless window with transparent panel transparency and window level. A panel that uses `NSBorderlessWindowMask` can’t become key unless you implement [`canBecomeKey`](/documentation/AppKit/NSWindow/canBecomeKey) to return <doc://com.apple.documentation/documentation/Swift/true>. Note that you can also set a panel’s style mask to `NSBorderlessWindowMask` in Interface Builder by deselecting Title Bar in the Appearance section of the Attributes inspector.
- `NSTitledWindowMask` `|` `NSUtilityWindowMask`: Titled window with transparent panel transparency and window level. This combination can be additionally combined with any of the following:
  - `NSClosableWindowMask`: Titled window with transparent panel close box, transparency, and window level.
  - `NSResizableWindowMask`: Titled window with transparent panel resize corner, transparency, and window level.
  - `NSNonactivatingPanelMask`: No effect on appearance, but owning app is not necessarily active when this window is the key window.

The following constants cannot be combined with `NSHUDWindowMask`: `NSMiniaturizableWindowMask`, `NSTexturedBackgroundWindowMask`, `NSDocModalWindowMask`, and `NSUnifiedTitleAndToolbarWindowMask`.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)