Ok a short explaination on the docked mode is that the uncovered pixels are needed to offset a bug.
Try to dock left with this skin [link]
On my pc once the Winamp slides to hide it doesn't come back (strange though dock right works ok).
The cause is that the skin is trimed on both sides (I wanted a borderless look).
I can make it so that it docks to the side flush on first appearance but the pixels come back on subsequent slide outs, which makes it pretty redundent.
For the volume bar, I think its because I did away with the thumb.
Might be able to do something about it.
Thanks for using the skin!