Thanks for writing.
The reordering of items within the source collection of the DataBoundListBox control happens synchronously with the reordering of visual items, i.e. items are reordered in the source collection as soon as you start changing the order via the User Interface.
Can you please share with us a sample that demonstrates your issue so that we can take a look and see what goes wrong? Normally you should have your items ordered in the source collection.
the Telerik team