Hi Naveed,
the ListBoxSelectionMode.One only works with non-nested tables, not with nested tables. We are working on a selection mechanism also for nested tables for the next version.
For your specific requirements you should therefore not use ListBoxSelectionMode.One. Instead we recommend handling PrepareViewStyle and simply highlighting the current record.
That attached sample
HighlighCurrentRecord2109_5329.zip shows how to do this. It also demonstrates how to navigate the current record between nested tables (we''ll also make this a built-in option in future releases).
Stefan