ParaJVD ... A rough sketch
This is a picture of a ParaJVD test framework that I coded to evaluate several Java Docking libraries. It is not functional at all (I was merely playing with windowing / docking features), so until I state otherwise, just take it for what it is right now : Vaporware :)
The version in this snapshot makes use of VLDocking ; I really enjoy its Look & Fell as well as its API... So it's well on its way to be my pick.