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# resizeFlags

The flags field of the event record for the mouse-down event that initiated the resizing session.

```
var resizeFlags: NSEvent.ModifierFlags { get }
```

## Discussion

The value of this property is a mask indicating which of the modifier keys was held down when the mouse-down event occurred. The flags are listed in [`NSEvent`](/documentation/AppKit/NSEvent) class’s [`modifierFlags`](/documentation/AppKit/NSEvent/modifierFlags-swift.property) method description. The property is valid only while the window is being resized.

You can use this property to constrain the direction or amount of resizing. Because of its limited validity, this property should only be accessed from within an implementation of the delegate method [`windowWillResize(_:to:)`](/documentation/AppKit/NSWindowDelegate/windowWillResize(_:to:)).

---

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