Hi Ohhh,
I presume that AdministrationToolStripMenuItem has a sub menu item: UserAccountToolStripMenuItem.
I try the following code in VB 2005 and VB 2008 and they work fine.
Maybe the sub menu item: UserAccountToolStripMenuItem has been set as Visible = False before showing current form.
You can create newWinForms project totry the code.
Code Snippet
Public Class Form1
' Hide the sub menu item
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
AdministrationToolStripMenuItem.DropDownItems("UserAccountToolStripMenuItem").Visible = False
End Sub
'Show the sub menu item
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
AdministrationToolStripMenuItem.DropDownItems("UserAccountToolStripMenuItem").Visible = True
End Sub
End Class