Child form not showing up in MDIcontainer's split Container

[marinajogy]

hi see the code below
1. i placed form and made it isMDIcontainer=true
2. added treeview to this form and docked to left
3. added split Container
4. added 2 child forms namde Form3 & Form4

everything ok, except one thing the child forms not showing up
help me

Public Class Form2
    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Call FillTreeView()
 End Sub

    Private Sub FillTreeView()
        Dim nodX As TreeNode
        Dim nodChild As TreeNode

        With tvwMenu
            .BeginUpdate()

            'Add the First Parent
            nodX = New TreeNode("Hardcoded elements")
            nodChild = New TreeNode("Child1")
            nodChild.Tag = "Form3"
            nodX.Nodes.Add(nodChild)
            nodChild = New TreeNode("Child2")
            nodChild.Tag = "Form4"
            nodX.Nodes.Add(nodChild)
            .Nodes.Add(nodX)
            nodX = Nothing

            'Add the parent for the dynamic elements
            nodX = New TreeNode("Dynamic elements")
            .Nodes.Add(nodX)
            nodX = Nothing

            .EndUpdate()
        End With
    End Sub

    Private Sub tvwMenu_DoubleClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles tvwMenu.DoubleClick
        Dim temp As String
        Try
            Select Case DirectCast(tvwMenu.SelectedNode.Tag, String)
                Case String.Empty
                    'Do Nothing
                Case "Form3"
                    Dim frm As New Form3()
                    temp = frm.Text
                    With frm
                        .MdiParent = Me
                        .FormBorderStyle = FormBorderStyle.None
                        .Show()
                        .Dock = DockStyle.Fill                        
                    End With
                Case "Form4"
                    Dim frm As New Form4()
                    temp = frm.Text
                    With frm
                        .MdiParent = Me
                        .Show()
                        .Dock = DockStyle.Fill
                    End With
                Case Else
                    MessageBox.Show("Houston, we have a problem!")
            End Select
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try

        MessageBox.Show(temp)
    End Sub
End Class