How to triggered when adding or removing QuickAccessToolbar items event in WinForms RibbonControlAdv?

public Form1()
{
    InitializeComponent();
    this.ribbonControlAdv1.Header.QuickItemAdded+=new ToolStripItemEventHandler(Header_QuickItemAdded);
    this.ribbonControlAdv1.Header.QuickItemRemoved += new ToolStripItemEventHandler(Header_QuickItemRemoved);
}
private void Header_QuickItemAdded(object sender, ToolStripItemEventArgs e)
{
    MessageBox.Show(e.Item.Text);
}
private void Header_QuickItemRemoved(object sender, ToolStripItemEventArgs e)
{
    MessageBox.Show(e.Item.Text);
}

Public Sub New()
    InitializeComponent()
    AddHandler ribbonControlAdv1.Header.QuickItemAdded, AddressOf Header_QuickItemAdded
    AddHandler ribbonControlAdv1.Header.QuickItemRemoved, AddressOf Header_QuickItemRemoved
End Sub
Private Sub Header_QuickItemAdded(ByVal sender As Object, ByVal e As ToolStripItemEventArgs)
    MessageBox.Show(e.Item.Text)
End Sub
Private Sub Header_QuickItemRemoved(ByVal sender As Object, ByVal e As ToolStripItemEventArgs)
    MessageBox.Show(e.Item.Text)
End Sub