I have Compiz enabled and use the 3D desktop cube with rotation as long as various cool minimize animations.
Recently when I boot the computer, Docky has been telling me to 'enable compositing'. I don't know what compositing is! Docky is working fine as it always has been though, so I don't know why it is suddenly asking me this (I'm guessing it is confused and that it is actually enabled but I'm not sure).
So what is compositing and is it enabled because I am using Compiz or is it something different?
What does 'compositing' mean exactly?
Compositing is provided by Compiz, which is a compositing window manager. What it means is explained below:
If you see a black border around docky, then compositing is not properly enabled. The warning you are getting is most likely a result of Docky starting before compositing kicks in.
See https://bugs.launchpad.net/docky/+bug/552273