static void richEditControl1_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
        {
            RichEditControl richEdit = sender as RichEditControl;

            System.Drawing.Point docPoint =
                DevExpress.Office.Utils.Units.PixelsToDocuments(e.Location, richEdit.DpiX, richEdit.DpiY);

            DocumentPosition pos = richEdit.GetPositionFromPoint(docPoint);

            if (pos == null)
            {
                return;
            }
            string currentToolTipText = String.Format("Position: {0}, Character: {1}", pos.ToString(),
                                                      richEdit.Document.GetText(richEdit.Document.CreateRange(pos, 1)));

            DevExpress.Utils.ToolTipControlInfo info =
                new DevExpress.Utils.ToolTipControlInfo(currentToolTipText, currentToolTipText);
            info.ToolTipPosition = System.Windows.Forms.Form.MousePosition;
            testToolTipController.ShowHint(info);
        }