Public Class Form1
 
    Private f As New Form
    Private panel1 As New Panel
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Me.IsMdiContainer = True
 
        panel1.Width = 100
        panel1.Dock = DockStyle.Left
 
        Me.Controls.Add(panel1)
 
        f.MdiParent = Me
        f.Show()
    End Sub
End Class