private void ValidateAutoComplete()
        {
            var constant = autoComplete.GetSelectedItem() as Constant;

            if (constant != null)
            {
                int position = textBoxWorkstring.SelectionStart;
                textBoxWorkstring.Text           = textBoxWorkstring.Text.Insert(position, "{" + constant.ID + "}");
                textBoxWorkstring.SelectionStart = position + constant.ID.Count() + 2;    //size of ID + braces

                CloseAutoComplete();
            }
        }