The DetachedTabs is a sort of TabSheet, with the tabs detached from its sheet. This component is merely the tabs for a tabsheet. The sheet itself is an external object. These two may be placed anywhere, independent of each other. This mechanism allows for a more flexible layouts, and you may place other widgets right alongside it, or somewhere totally disconnected, and you are not constrained by the "bounding box" presented by the TabSheet's tabs+sheet combination.