DataGridView Scroll show columns over others

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

Attachment 159965

i have tried DoubleBuffered like that:

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

2- i add that code in it:

Code:

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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


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3- i call that module in Load Event:

Code:

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DoubleBuffer.DoubleBuffered(DataGridView1,True)

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but it give me BLACK Cells

so, what is the problem i faced here?