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# mouseDown(with:)

Informs the gesture recognizer that the user pressed the left mouse button.

```
func mouseDown(with event: NSEvent)
```

## Parameters

`event`

An object encapsulating information about the mouse-down event.

## Discussion

The default implementation of this method does nothing. Use this method to start tracking the gesture in whatever way is appropriate.

A gesture recognizer monitors events that occur in its view (and any subviews) but does not take part in the responder chain itself. The gesture recognizer receives events before any views do. Use the [`delaysPrimaryMouseButtonEvents`](/documentation/AppKit/NSGestureRecognizer/delaysPrimaryMouseButtonEvents) property to control whether `event` is propagated to the view.

---

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