private void ultraExplorerBar1_NavigationPaneFlyoutDisplayed( object sender, EventArgs e )
{
    UltraExplorerBar explorerBar = sender as UltraExplorerBar;
    NavigationPaneFlyoutContainerControl flyout =
        DropDownManager.GetCurrentDropDownControl( explorerBar )
        as NavigationPaneFlyoutContainerControl;

    if ( flyout != null )
    {
        flyout.Resize -= new EventHandler(this.flyout_Resize);
        flyout.Resize += new EventHandler(this.flyout_Resize);
    }
}

private void flyout_Resize(object sender, EventArgs e)
{
}