Private Sub UserControl1_Resize(ByVal sender As Object, ByVal e As _
  SystemEventArgs)Handles Me.Resize
    Me.Width = Me.Parent.Width ' Auf die Breite des übergeordneten COntrols 
    ' festlegen
    Me.Left = 0 'Auf Position 0
    Me.Height = 2 'Höhe immer gleich bleibend
End Sub
'Code von WmS:
    Private Sub UserControl1_Paint(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        e.Graphics.DrawLine(New Pen(SystemColors.ControlDark), 0, 0, Me.Width, _
        0)
        e.Graphics.DrawLine(New Pen(SystemColors.ControlLightLight), 0, 1, _
        Me.Width, 1)
    End Sub