Drag'n'drop a tab out from container to
either
a). detach it into a separate container (i.e. into a 1-tabbed TS container)
or
b). release all of it's windows from a container at all (back to normal windows)
and provide a setting to let the user choose preferred behavior.
Drag'n'drop a tab from one container into another (just in case you'd like re-organize meta-containers [TS windows]).