Performance issue on DataGrid

Hi,

I searched similar threads here before submitting mine, but the difference I am experiencing with the rest is that I only have 15 rows and Not 5000.  I have user controls displaying as tabs on main screen and every time I open or click on the tab with gridView I notice a slight delay. 

The reason I am posting this is that it's only 15 rows and I am not sure what is going to be when this can easily grow to 15000 ?  I have posted the code as I might be doing something horribly wrong here.

<Border DockPanel.Dock="Top"
            Style="{StaticResource ViewBorderStyle}"
            Margin="10,10,10,10"><DataGrid 
                AutoGenerateColumns="True"
                ItemsSource="{Binding Path=AllCustomersList}">   </DataGrid></Border>

The binding source is of IList<Customer> type.