null is not an object

I have finally signed up for Backpack in the last couple of days to check it out and it seems that someting strange is going on - when I add items to my task list they are being added using synchronous requests rather than asynchronous. After clicking the add to list button the trendy Mac processing animated gif appears as the item is saved to the server. Once saved to the server the user interface is finally updated with the item and I can proceed to add more items.

This is strange since it actually makes for something more like SJAX rather than AJAX. Granted they could well have a good business reason for doing so but if you look at Flickr then you will see that you can add tags to photos pretty quickly because there is no waiting for the server response.