Modifications to this document are under review.
A Pane (Tab) Group is an interface element that allows functionality exposed at the top-level of the interface to be stacked within the same area, with an easy to use selection mechanism for pulling items lower in the stack to the front.
A Pane Group exists only as a container for a Pane (Tab), or a stack of Panes, and a set of common controls that provide general conveniences for working with them. A Pane Group can be anchored, or docked, within a Dock Area. They can be made to float, or undocked, in a dockable frame. They can also be made undockable, by being placed within a non-modal child window.
Below is a list of interface elements that a Pane Group can exist within: