It seems like the “Add to my Bag” feature is broken. When searching for an item you can click the chevron-down icon to expand the row and expose the ilvl dropdown selector. However, as soon as you select an item level for the item and hit apply the item just disappears from the list and is not “added to your bags” and will not reappear in the list until you reload the page.
It’s possible that this is fixed in our latest dev build (we’re pretty busy preparing for 10.1.5). Try it again after the update this coming Tuesday and if you are still having an issue, post a snapshot ID using the “help” link next to any section header on the optimizer page and we’ll take a look.