private Sub checkbox_CheckedChange(Checked As Boolean)
Dim chk As CheckBox = Sender
Dim index As Int = chk.Tag
Dim arr() As Object = tw.Items.Get(index)
tw.Items.RemoveAt(index)
If Checked Then
tw.Items.InsertAt(0,arr)
Else
tw.Items.InsertAt(tw.Items.Size -1,arr)
End If
End Sub