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# becomeMain()

Informs the window that it has become the main window.

```
func becomeMain()
```

## Discussion

This method posts an [`didBecomeMainNotification`](/documentation/AppKit/NSWindow/didBecomeMainNotification) to the default notification center.

Never invoke this method directly.

## See Also

[`becomeKey()`](/documentation/AppKit/NSWindow/becomeKey())

Informs the window that it has become the key window.


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