private void PerformSearch(object sender, EventArgs e)
        {
            var ids = indexer.GetIds(request.Text);

            results.Controls.Clear();
            var y = 0;

            foreach (var id in ids)
            {
                RichTextBox box = new RichTextBox();
                box.Text = texts[id];
                foreach (var position in indexer.GetPositions(id, request.Text))
                {
                    box.Select(position, request.Text.Length);
                    box.SelectionBackColor = Color.LightBlue;
                }
                box.ReadOnly = true;
                box.Size     = new Size(results.Width, 50);
                box.Location = new Point(0, y);
                y           += box.Height;
                results.Controls.Add(box);
            }
        }