Fantastic! Managing views in eclipse like this is one of the things that keeps me using eclipse.
From looking at the demo and the docs...
What I didn't see in the demo was changing the order of a tab within a panel via drag-and-drop (no "allowIntraPaneTabMove"?). Also presuming you can close tabs to left, right, or all other tabs (would need tabs as list to implement this in application). Also might like to somehow manage title elision when there are multiple tabs. Also want to change pane proportions on the fly. Also assuming one can have two views of the same document in different tabs.
So many possibilities! I'll try it in some app...