Here's a small example that puts together several pieces in the context of a NetBeans Platform application, i.e., TopComponent, Node, Lookup, Palette, and Visual Library:
http://java.net/projects/nb-api-samples/sources/api-samples/show/versions/7.2/misc/CensusDesigner
The result is a drag-and-drop user interface, i.e., drag items from the palette and drop them onto the window, that's all it does, nothing too fancy, just puts the basic NetBeans Platform pieces together in a pretty standard combination: