using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using Telerik.Web.UI;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        RadListBox1.Transferring += new RadListBoxTransferringEventHandler(RadListBox1_Transferring);

    }

    void RadListBox1_Transferring(object sender, RadListBoxTransferringEventArgs e)
    {
        e.Cancel = true;

        foreach (var item in e.Items)
            e.DestinationListBox.Items.Add(item);
    }
}