This script was the result of testing i've been doing. I was trying to understand how to build AE dockable scripts. While this is NOT the only way to create them, this turned out to be a more understandable method for my own brain.
I wanted to start with a simple task for the test of building buttons and a UI. I chose Lloyd Alvarez's duplicate layer script that he taught to an audience at a recent AENY presentation http://www.vimeo.com/3031889.
This simple script was a good place for me to start building a UI. Along the way of building the UI for Lloyd's script I gathered various code information from other scripts created by Lloyd Alvarez, Jeff Almasol, Ian Haigh and got direct help from Paul Tuersley.
I do not claim this script as my own, but felt it a useful one to share just in case it was not out there already. Plus I also felt that maybe it would also aid those who like myself were trying to get a handle on one possible way to build AE script UI's. I added a bunch of comments within the script to explain as best I could what each line of code does.
Place the .jsx file in the "ScriptUI Panels" folder.