Color public property of custom user control problem

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Text;
using System.Windows.Forms;
 
namespace gridCustomControl
{
    public partial class GridCustomControl : UserControl
    {
        private int _cols;
        private int _rows;
        private int _width;     // Cell width
        private int _height;    // Cell height
        private float _zoom;
        private Color _cellColor;
        private Color _borderColor;
 
        public GridCustomControl()
        {
            InitializeComponent();
 
            // The following SetStyles are needed for double buffering:
            SetStyle(ControlStyles.DoubleBuffer, true);
            SetStyle(ControlStyles.AllPaintingInWmPaint, true);
            SetStyle(ControlStyles.UserPaint, true);
 
            _cols = Cols;
            _rows = Rows;
            _width = CellWidth;
            _height = CellHeight;
            _cellColor = CellColor;
            _borderColor = BorderColor;
 
            this.ControlSize = new Size(_width * _cols, _height * _rows);
        }
 
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            Graphics g = e.Graphics;
            g.FillRectangle(Brushes.White, this.ClientRectangle);
 
            int cellHeight = this.CellHeight;   
            int cellWidth = this.CellWidth; 
            int nbrColumns = this.Cols;
            int nbrRows = this.Rows;
 
            // Draw cells
            for (int row = 0; row < nbrRows; row++)
            {
                for (int col = 0; col < nbrColumns; col++)
                {
                    Point cellLocation = new Point(col * cellWidth, row * cellHeight);
                    Rectangle cellRect = new Rectangle(cellLocation.X,
                                                       cellLocation.Y,
                                                       cellWidth, cellHeight);
 
                    if (cellRect.IntersectsWith(e.ClipRectangle))
                    {
                        g.FillRectangle(new SolidBrush(_cellColor), cellRect);
                        g.DrawRectangle(new Pen(_borderColor, 1), cellRect);
                    }
                    else
                    {
                        // Do nothing...
                    }
                }
            }
            this.Invalidate(); // Redraw the whole control
        }
 
        [Browsable(true),
            DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
 
        public int Cols
        {
            get { return _cols; }
            set { _cols = value; }
        }
 
        public int Rows
        {
            get { return _rows; }
            set { _rows = value; }
        }
 
        public int CellWidth
        {
            get { return _width; }
            set { _width = value; }
        }
 
        public int CellHeight
        {
            get { return _height; }
            set { _height = value; }
        }
 
        public float Zoom
        {
            get { return _zoom; }
            set { _zoom = value; }
        }
 
        public Size ControlSize
        {
            // This property references the 'this' because there
            // aren't any private members that need to be created
            // to hold the size value.
 
            get { return this.Size; }
            set 
            {
                _width = value.Width;
                _height = value.Height;
 
                // 1 is added otherwize the most very most right line and
                // the very most bottom line will not show.
                this.Size = new Size(_width * _cols + 1, _height * _rows + 1);
 
                this.Invalidate(); // Redraw the whole control
            }
        }
 
        public Color CellColor
        {
            get { return _cellColor; }
            set { _cellColor = value; }
        }
 
        public Color BorderColor
        {
            get { return _borderColor; }
            set { _borderColor = value; }
        }
    }
}