The autocomplete is supposed to quick fill the rest of the item name _but_ leave the "guessed" part selected.  So if you type an additional character it should further refine the guess. 

So as you type lrglav-w when you get to the "a" character it should refine the estimate since Irglv-T no longer matches "Irgla".   

Is it not doing that? The key is to not tab to the next field until after you type the "a".