Sometimes Blizzard doesn’t autorefresh your collection, which causes issues with tracking. It’s also a good idea to do this fairly regularly, especially if you’re having issues with items showing as uncollected when you know you have them. We suggest that you SHIFT+CLICK the “ALL THE THINGS” header to force a refresh of your collection when you first install.
These can be freely moved around the screen, resized, and closed. There are two central lists displayed by ATT.