Dim g = PictureBox1.CreateGraphics
        Dim x As Integer
        x = ListBox1.SelectedIndex
        ListBox1.Refresh()
        PictureBox1.Refresh()
 
 
            g.FillRectangle(New SolidBrush(Color.FromArgb(50, _
              Color.LightSlateGray)), xcor(x), ycor(0), xcor(x + 1) - xcor(x), _
              ycor(1) - ycor(0))
            g.DrawRectangle(New Pen(Color.Black, 5), xcor(x), ycor(0), xcor(x + _
            1) - xcor(x), ycor(1) - ycor(0))
            LB_SetIndex(ListBox1, x)
 
    ListBox1.Refresh()

Gruss Caddy