---
title: "comboBoxWillPopUp(_:)"
framework: appkit
role: symbol
role_heading: Instance Method
path: "appkit/nscomboboxdelegate/comboboxwillpopup(_:)"
---

# comboBoxWillPopUp(_:)

Informs the delegate that the pop-up list is about to be displayed.

## Declaration

```swift
@MainActor optional func comboBoxWillPopUp(_ notification: Notification)
```

## Parameters

- `notification`: A notification named doc://com.apple.appkit/documentation/AppKit/NSComboBox/willPopUpNotification.

## See Also

### Manipulating the selection

- [comboBoxSelectionDidChange(_:)](appkit/nscomboboxdelegate/comboboxselectiondidchange(_:).md)
- [comboBoxSelectionIsChanging(_:)](appkit/nscomboboxdelegate/comboboxselectionischanging(_:).md)
- [comboBoxWillDismiss(_:)](appkit/nscomboboxdelegate/comboboxwilldismiss(_:).md)