using callout as a tooltip ?

        public RadForm1()
        {
            InitializeComponent();

            this.radGridView1.Columns.Add("Id");
            this.radGridView1.Columns.Add("Name");
            for (int i = 0; i < 10; i++)
            {
                this.radGridView1.Rows.Add(i, Guid.NewGuid().ToString());
            }
            this.radGridView1.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill;
             

            label = new RadLabel();
            label.Text = "Telerik";
            callout = new RadCallout();
            callout.AssociatedControl = label; 

           this.radGridView1.ToolTipTextNeeded+=radGridView1_ToolTipTextNeeded;
        }

        private void radGridView1_ToolTipTextNeeded(object sender, ToolTipTextNeededEventArgs e)
        {
              Point pt = this.radGridView1.PointToClient(MousePosition);
            GridDataCellElement cellUnderMouse = this.radGridView1.ElementTree.GetElementAtPoint(pt) as GridDataCellElement;
            if (cellUnderMouse != null)
            { 
                label.Text = cellUnderMouse.Value + "";
                if (callout.CalloutForm.Visible)
                {
                    callout.Close();
                }
                callout.Show(cellUnderMouse);
            }
        }

        RadCallout callout;
        RadLabel label; 
    }