Dim drawBm As Boolean
 
    Private Sub PaintVeil(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        If drawBm Then
            Using b As SolidBrush = New SolidBrush(Color.FromArgb(128, 0, 0, 0))
                e.Graphics.FillRectangle(b, 0, 0, Me.ClientSize.Width, _
                  Me.ClientSize.Height)
            End Using
        End If
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        drawBm = Not drawBm
        If drawBm Then
            For Each c As Control In Me.Controls
                AddHandler c.Paint, AddressOf PaintVeil
            Next
            AddHandler MyBase.Paint, AddressOf PaintVeil
        Else
            For Each c As Control In Me.Controls
                RemoveHandler c.Paint, AddressOf PaintVeil
            Next
            RemoveHandler MyBase.Paint, AddressOf PaintVeil
        End If
        Me.Refresh()
    End Sub

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