I want to sort my Pivot Table manually but I can't find out how.

I went to More Sort Options and I selected Manual. It says in the summary that I can "Drag items of the Plane Model field to display them in any order". I can't find the items in my "Plane Model" field that can be dragged. They are visible in the pivot table, but not in the field. I'm using Excel 2007.

Any help?