With the latest Spring Release, you're no longer able to get a whole list of Portfolio Items and Child Portfolio Items when you create a backlog item. The drop-down menu is great if you know your exact Epic number, but otherwise we are not finding this to be very useful. Adding a feature to expand Portfolio Items, if Child Portfolio Items live underneath, would be very useful when creating a backlog item so you don't have to save it, and then go back in and edit the Portfolio Item.