Private Sub Form2ToolStripMenuItem_Click(sender As System.Object, e As System.EventArgs) Handles Form1ToolStripMenuItem.Click
If TryCast(Application.OpenForms("Form2"), Form2) IsNot Nothing Then
Else
Dim frm As Form2 = New Form2()
frm.MdiParent = Me
frm.Show()
End If
End Sub