Also, a preview of new features in the next release:
Due to popular request, icons can now be centered or right justified in Shelves (tabbed docks).
Icons in docks, Shelves, etc, can now be colorized using one of three different methods (Tint, Hue or Tone). Tint is the most useful method for icon colorization, unless the icons are black, in which case you should use Tone.
As you can see you should use Tone when colorizing solid black icons, and Tint otherwise.
Using a solid black color together with Tint is also a great way to quickly grayscale all the icons: