public MDIForm()
        {
            InitializeComponent();
            this.radRibbonBar1.RibbonBarElement.ItemVisiblityStateChanging += this.RibbonBarElement_ItemVisiblityStateChanging;
        }

        private void RibbonBarElement_ItemVisiblityStateChanging(object sender, ItemVisiblityStateChangingEventArgs args)
        {
            if (args.NextVisibilityState == ChunkVisibilityState.NoText)
            {
                args.Cancel = true;
            }
        }