DataView and DataGrid

Why when I bind the dataview to datagrid control I can't add new records in datagrid ???
When I bind the actual dataset, I can! Even when I set dataviews "allow new" property to true, the data grid stil refuses to accept the new row !

I use this code to create dataview and bind it:

Dim dvv As New DataView(data_set.Tables("people"))
dvv.AllowDelete = True
dvv.AllowEdit = True
dvv.AllowNew = True
dvv.RowFilter = "name='mike'"
DataGrid1.SetDataBinding(dvv, Nothing)

The datagrid become populated with correct data, but when I type new data in last row marked with "*" (the row for adding new records) and then when I move cursor outside of that row, the new row disapears.

Help !