Roland Collins made a good point about the slushy code - if you don't maintain order when you shift items left and right, it gets a bit distracting. He made a small mod to my code (err, Ron's code really) to help maintain order. Whenever you do the "All Left" or "All Right", the items that move maintain their order.
Now, to be anal, it only remembers the orders of the items shifting. So imagine you have A, B, and C in the left column. If you move C to the right, then move all to the right, you end up with C, A, B. It kept "A" and "B" in the right order, but didn't remember that originally it was A,B,C. However, this is still better than the way I had it. Download link is in My Tools (or will be in 120 seconds).