MaskedTextBox Problem

Hello everyone.
Ok. What point am I missing here.
Visual Studio 2010, Basic.
If you
1- make Form1
2- Add Panel1 to Form1
3- make Form2
4- add Button1, TextBox1 and MaskedTextBox1 to Form2
5- put this code in the Form1

Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
Dim formgr As New Form2
formgr.TopLevel = False
formgr.WindowState = FormWindowState.Maximized
Me.Panel1.Controls.Add(formgr)
formgr.Show()
End Sub

*** Note no code required for Form2.
I am expecting to be able to add text to the MaskedTextBox , but no , it will not take input.
Both Button1 and Textbox1 work as expected.
If I set the startup form from form1 to form2 ,Button1, Textbox1 and MaskedTextBox1 work as expected.

Any ideas ?