Private Const WM_PAINT As Integer = 15

    Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
        If m.Msg = WM_PAINT Then
            Invalidate()

            MyBase.WndProc(m)

            Using g As Graphics = Graphics.FromHwnd(Handle)
                g.DrawLine(Pens.Blue, New Point(1, 1), New Point(10, 15))
            End Using
        Else
            MyBase.WndProc(m)
        End If
    End Sub