The simplest level of combining several panels together is a Group. This layer allows to arrange several panels as nested tabs and then move the created group as one panel.
To group two panels just click and drag one Panel’s header over another. To ungroup panels just drag an active Panel’s tab out of group tabs bar.
Panels can also be reordered within group tabs as well as closed being grouped. Each newly created group has a default name “Group” that can be easily changed via panel’s context menu.