DataGridView Scroll show columns over others

[M.G.R]

I have a datagridview, and when i use scrollbar the columns shown over the others, like this image:



i have tried DoubleBuffered like that:

1- i created a module named "DoubleBuffer.vb"

2- i add that code in it:

Imports System
Imports System.Reflection
Imports System.Windows.Forms
Module DoubleBuffer
    PublicSub DoubleBuffered(ByVal dgv As DataGridView,ByVal setting AsBoolean)
        Dim dgvType As Type = dgv.[GetType]()
        Dim pi As PropertyInfo = dgvType.GetProperty("DoubleBuffered", BindingFlags.Instance Or BindingFlags.NonPublic)
        pi.SetValue(dgv, setting,Nothing)
    EndSub
EndModule

3- i call that module in Load Event:

DoubleBuffer.DoubleBuffered(DataGridView1,True)

but it give me BLACK Cells

so, what is the problem i faced here?