I'm going to try the DataTemplate approach now that I have more time to play around with it (and not under project deadline pressure to "make it work anyway possible").
As I remember, when using v1.3 and I switched tabs, the combobox selecteditems were refreshing ok but it was the DataGrid selecteditems that I couldn't get to refresh. Now that our company purchased DevExpress controls, I'm using their GridControl which has a solution to the selecteditems binding problem (http://www.devexpress.com/Support/Center/p/B190790.aspx) that isn't workable in DataGrid from Microsoft.
So, with that in place I can allow the controls to re-generate when tabs are changed, knowing that the selections will remain intact.
I think the performance issues I came across were experienced while running my project from the Visual Studio debugger. I will try again with a stand-alone executable.
Steve