The ButtonClick event notifies your application that the user clicks a button. The AddButton method adds a new button to the editor. Also, the ButtonClick event is fired when user clicks the drop down button of an editor of one of the following types: DropDown, DropDownList, CheckList, Date, Color, Font, Picture, PickEdit and Button . In this case, the Key parameter is an empty string.

The following sample displays the key of the button that user clicked:

Private Sub Editor1_ButtonClick(ByVal Key As Variant)
    Debug.Print "The user clicks the " & IIf(Key = "", "drop down", "'" & Key & "'") & " button"
End Sub

Private Sub Form_Load()
    With Editor1
    
        .EditType = DropDownList
        .AddItem 1, "One"
        .AddItem 2, "Two"
        
        .AddButton "KeyA", 1
        
        .Value = 1
    End With
End Sub