Column Boundaries getting overlapped in Telerik Grid for Winforms

I am working on Winform application. Using Telerik controls on it.

On 1 form, I need to have composite columns as in image below. These columns have been added dynamically(through C#), I have used HTMlViewDefinition.

The problem is, columns boundaries are getting overlapped as in image below.

I need the column width to be decided at run time, so don't want to give static width to them.

Code, I have written for this grid is as below

var htmlView = new HtmlViewDefinition()
                {

                };
                htmlView.RowTemplate.Rows.Add(new RowDefinition());
                htmlView.RowTemplate.Rows.Add(new RowDefinition());

                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("No"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("Item No"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("UOM"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("Pres QTY"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("Disp QTY"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("Refill QTY"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("Dose"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("No of Days"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("English Direction"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("No of Packs"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("Drug Location"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("Available QTY"));

                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("Machine Available QTY"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("Shelves Available QTY"));


                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("Remain to Verify"));
                htmlView.RowTemplate.Rows[0].Cells.Add(new CellDefinition("Verification Status"));

  htmlView.RowTemplate.Rows[0].Cells[0].RowSpan = 2;
                htmlView.RowTemplate.Rows[0].Cells[3].RowSpan = 2;
                htmlView.RowTemplate.Rows[0].Cells[4].RowSpan = 2;

                htmlView.RowTemplate.Rows[0].Cells[3].ColSpan = 1;
                htmlView.RowTemplate.Rows[0].Cells[4].ColSpan = 1;

                htmlView.RowTemplate.Rows[0].Cells[5].RowSpan = 2;
                htmlView.RowTemplate.Rows[0].Cells[6].RowSpan = 2;
                htmlView.RowTemplate.Rows[0].Cells[7].RowSpan = 3;


 htmlView.RowTemplate.Rows[0].Cells[9].RowSpan = 2;
                htmlView.RowTemplate.Rows[0].Cells[10].RowSpan = 2;
                htmlView.RowTemplate.Rows[0].Cells[11].RowSpan = 2;
                htmlView.RowTemplate.Rows[0].Cells[12].RowSpan = 2;
                htmlView.RowTemplate.Rows[0].Cells[13].RowSpan = 2;

                htmlView.RowTemplate.Rows[0].Cells[14].RowSpan = 2;
                htmlView.RowTemplate.Rows[0].Cells[15].RowSpan = 2;


 htmlView.RowTemplate.Rows[0].Height = 30;

                htmlView.RowTemplate.Rows[1].Cells.Add(new CellDefinition("Item Description"));
                htmlView.RowTemplate.Rows[1].Cells[0].ColSpan = 2;
                htmlView.RowTemplate.Rows[1].Cells.Add(new CellDefinition("Direction"));
 htmlView.RowTemplate.Rows[1].Height = 30;
 gridDrugList.BestFitColumns();

                gridDrugList.MasterTemplate.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill;

 gridDrugList.ViewDefinition = htmlView;