Как убрать обводку у текста

Imports System.Runtime.InteropServices
    <Runtime.InteropServices.StructLayout(Runtime.InteropServices.LayoutKind.Sequential)>
    Public Structure MARGINS
        Public LeftWidth As Integer
        Public RightWidth As Integer
        Public TopHeight As Integer
        Public Buttomheight As Integer
    End Structure
 
    <Runtime.InteropServices.DllImport("dwmapi.dll")>
    Public Shared Function DwmExtendFrameIntoClientArea(ByVal hWnd As IntPtr, ByRef pMarinset As MARGINS) As Integer
    End Function
 
    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        Me.Height = 251
        TextBox1.TextAlign = HorizontalAlignment.Right
        TextBox1.Text = "0"
        Me.Width = 315
        ОбычныйToolStripMenuItem.Checked = True
        Try
            Me.TransparencyKey = Color.Cyan 'контралах не используйте этот цвет, или меняйте
            Me.BackColor = Color.Cyan 'контралах не используйте этот цвет, или меняйте
            MainMenuStrip.BackColor = Color.Transparent
            Dim margins As MARGINS = New MARGINS
            margins.LeftWidth = -1
            margins.RightWidth = -1
            margins.TopHeight = -1
            margins.Buttomheight = -1
            Dim result As Integer = DwmExtendFrameIntoClientArea(Me.Handle, margins)
        Catch ex As Exception
            MsgBox("Ошибка" & Err.Description, vbCritical, "Fatal Error")
            Application.Exit()
        End Try
    End Sub

    Private Sub КToolStripMenuItem_Click(sender As System.Object, e As System.EventArgs) Handles КToolStripMenuItem.Click
        Clipboard.SetDataObject(TextBox1.Text)
    End Sub
 
    Private Sub ВставитьToolStripMenuItem_Click(sender As System.Object, e As System.EventArgs) Handles ВставитьToolStripMenuItem.Click
        Dim Inset As IDataObject = Clipboard.GetDataObject()
        TextBox1.Text = CType(Inset.GetData(DataFormats.Text), String)
    End Sub
 
    Private Sub Form1_KeyDown(sender As Object, e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
        If e.KeyCode = Keys.ControlKey + Keys.C Then
            Clipboard.SetText(TextBox1.Text)
        End If
        If e.KeyCode = Keys.ControlKey + Keys.V Then
            TextBox1.Text = Clipboard.GetText
        End If
    End Sub

  'Clipboard.SetData(DataFormats.Text, TextBox1.Text)
 
        'Clipboard.SetText(TextBox1.Text, TextDataFormat.UnicodeText)