Also in the same example if i reset issorted to None first and then set the sort order then i see there are four items added insted of three. update the two functions in the previous example then click the update layout button and then additems button, you'll see 4 rows in the grid instead of 3

private void AddItems(object sender, RoutedEventArgs e)
{
collection.Add(new Data() { Data1 = "Item 1"});
collection.Add(new Data() { Data1 = "Item 2" });
collection.Add(new Data() { Data1 = "Item 3" });
}

public void Sort()

{
var t = grid.Columns[0] as TextColumn;
t.IsSorted = SortDirection.None;
t.IsSorted = SortDirection.Ascending;
}