To reproduce: BindingList<string> items = new BindingList<string>(); public Form1() { InitializeComponent(); for (int i = 0; i < 5; i++) { items.Add("item" + i); } this.radDropDownList1.DataSource = items; this.radDropDownList1.SortStyle = Telerik.WinControls.Enumerations.SortStyle.Descending; } private void button1_Click(object sender, EventArgs e) { items.Add(DateTime.Now.ToLongTimeString()); } Workaround: keep the selection before adding the item and restore it after that: int index = this.radDropDownList1.SelectedIndex; items.Add(DateTime.Now.ToLongTimeString()); this.radDropDownList1.SelectedIndex = index;