A Collection window (previously called the "Collection's Tab") is a new UI element that was introduced in Warlords of Draenor that has tab panes with collections of items that could otherwise take up bag space. As of the Closed alpha build 18379 of Warlords of Draenor and at release, this window resembles the Mounts And Pets window (Mounts tab and Pet Journal tab) with the addition of a Toy Box tab. Initial plans were to have the Toy Box tab containing types of items restricted to Heirlooms and vanity items, but at release heirlooms were not included. A separate Heirlooms tab was added with Patch 6.1.