Imports System.Drawing
Imports System.Windows.Forms

Public Class Form1
   Inherits Form
   Private myTabRect As Rectangle

   Public Sub New()
      Dim tabControl1 As New TabControl()
      Dim tabPage1 As New TabPage()

      tabControl1.DrawMode = TabDrawMode.OwnerDrawFixed
      tabControl1.Appearance = TabAppearance.Buttons
      tabControl1.Location = New Point(25, 25)
      tabControl1.Controls.Add(tabPage1)
      Controls.Add(tabControl1)

      ' Gets a Rectangle that represents the tab page display area of tabControl1.
      myTabRect = tabControl1.DisplayRectangle

      myTabRect.Inflate(1, 1)
      AddHandler tabControl1.DrawItem, AddressOf DrawOnTabPage
   End Sub

   Private Sub DrawOnTabPage(sender As Object, e As DrawItemEventArgs)
      Dim g As Graphics = e.Graphics
      Dim p As New Pen(Color.Blue)
      g.DrawRectangle(p, myTabRect)
   End Sub

   Shared Sub Main()
      Application.Run(New Form1())
   End Sub
End Class

using System.Drawing;
using System.Windows.Forms;

public class Form1 : Form
{
    private Rectangle myTabRect;

    public Form1()
    {
        TabControl tabControl1 = new TabControl();
        TabPage tabPage1 = new TabPage();

        tabControl1.DrawMode = TabDrawMode.OwnerDrawFixed;
        tabControl1.Appearance = TabAppearance.Buttons;
        tabControl1.Location = new Point(25, 25);
        tabControl1.Controls.Add(tabPage1);
        Controls.Add(tabControl1);

        // Gets a Rectangle that represents the tab page display area of tabControl1.
        myTabRect = tabControl1.DisplayRectangle;

        myTabRect.Inflate(1, 1); 
        tabControl1.DrawItem += new DrawItemEventHandler(DrawOnTabPage);
    }

    private void DrawOnTabPage(object sender, DrawItemEventArgs e)
    {
        Graphics g = e.Graphics;
        Pen p = new Pen(Color.Blue);
        g.DrawRectangle(p, myTabRect);
    }

    static void Main() 
    {
        Application.Run(new Form1());
    }
}

using namespace System::Drawing;
using namespace System::Windows::Forms;
public ref class Form1: public Form
{
private:
   Rectangle myTabRect;

public:
   Form1()
   {
      TabControl^ tabControl1 = gcnew TabControl;
      TabPage^ tabPage1 = gcnew TabPage;
      tabControl1->DrawMode = TabDrawMode::OwnerDrawFixed;
      tabControl1->Appearance = TabAppearance::Buttons;
      tabControl1->Location = Point(25,25);
      tabControl1->Controls->Add( tabPage1 );
      Controls->Add( tabControl1 );

      // Gets a Rectangle that represents the tab page display area of tabControl1.
      myTabRect = tabControl1->DisplayRectangle;
      myTabRect.Inflate( 1, 1 );
      tabControl1->DrawItem += gcnew DrawItemEventHandler( this, &Form1::DrawOnTabPage );
   }


private:
   void DrawOnTabPage( Object^ /*sender*/, DrawItemEventArgs^ e )
   {
      Graphics^ g = e->Graphics;
      Pen^ p = gcnew Pen( Color::Blue );
      g->DrawRectangle( p, myTabRect );
   }

};

int main()
{
   Application::Run( gcnew Form1 );
}