How do I prerender the controls on a TabItem in WPF?

Question

C# XBap Application

I have a TabControl with four TabItems in it. Two of these TabItems simply contain a DataGrid from the WPFToolkit which pulls a fairly small datatable (100 rows by 4 columns) from a SQL Server database. My problem is that when I load my application and I click on one of the TabItems containing a datagrid. There seems to me a 2-3 second pause before it brings that tab into focus. This only happens the very first time the tab is clicked. It seems to be the rendering of the datagrid.

How can I make those tabs prerender when the application loads so that when a user clicks a tab, there is not that initial pause of 2-3 seconds before the tab shows up.

Thanks