Okay I am trying to draw a horzontal and vertical line through a point on the map.

Code:
 public partial class PaintBox : System.Windows.Forms.PictureBox
    {
        public PaintBox()
        {
            this.SetStyle(System.Windows.Forms.ControlStyles.AllPaintingInWmPaint | System.Windows.Forms.ControlStyles.UserPaint | System.Windows.Forms.ControlStyles.OptimizedDoubleBuffer, true);

            InitializeComponent();
        }

        public PaintBox(IContainer container)
        {
            container.Add(this);

            InitializeComponent();
        }
        
        protected override void OnPaint(System.Windows.Forms.PaintEventArgs pe)
        {
            System.Drawing.Pen mypen;
            mypen = new System.Drawing.Pen(System.Drawing.Color.Red);
            System.Drawing.Graphics gra = this.CreateGraphics();


            gra.DrawLine(mypen, 0, Program.mainForm.CurrentPoint.Y, this.Width, Program.mainForm.CurrentPoint.Y);
            gra.DrawLine(mypen, Program.mainForm.CurrentPoint.X, 0, Program.mainForm.CurrentPoint.X, this.Height);
            mypen.Dispose();
            gra.Dispose();
            base.OnPaint(pe);
        }
    }
I call an invalidate via a button link which passes the coordinates to the global points and displays the line although here is the problem. (I have a giant 6000 by 5500 picturebox with a map in it, located inside a panel and i am utilizing the scroll bars) As soon as I click the scrollbar to shift the picture the line disappears, although if I click the scroll bars fast you can see the lines properly but as soon as I stop clicking it disappears again.

I have absoulutely no Idea whats going on seing how I created a new project copied and pasted the same code and it works fine...any ideas?