Create MDI Child Forms

Private Sub CourseFeeToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CourseFeeToolStripMenuItem.Click

Dim NewMDIChild As New Frm_course_fee()
'Set the Parent Form of the Child window.
NewMDIChild.MdiParent = Me
'Display the new form.
NewMDIChild.Show()
End Sub

Please note main form ismdicontainer=true