It is quite funny that SharpDevelop 3 uses an old version of DPS (version 2.1). This really helps me locate what changes DPS 2.2 introduces, and at last I find out how to merge these two versions to please myself.
In this post I said that the tab background colour is darker and from source code I know why and how to make it lighter. Merge a line of 2.1 source code into 2.2 source code and everything goes fine.
There are other changes, but I feel in most cases 2.2 is better. So I would continue using 2.2.
Now I am hoping that someone can design an Office 2007 style DPS so I can use it with Krypton Toolkit.
(Updated: Now I become a maintainer of DockPanel Suite. The latest DPS can be found at https://github.com/dockpanelsuite/dockpanelsuite.)