Regular visitors to Cool Focus will recognize this as the menu we used to use for the site's main navigation.
In this example, the tree items and toggle buttons behave like 3D buttons, and the scrollbar has a 3D style with a 'push-in' effect. (The scrollbar is set to auto-hide in this example.)
You can also see that Nexus allows horizontal separator-lines to be used to divide the menu into sections.
Finally, you can see that Nexus has intelligent 'scroll-into-view' features. For example, expand Flash Applet Gallery, then Text Displays, and then expand How to Buy at the bottom of the tree. The menu adjusts automatically to display the contents of the expanded branch.