But the best thing is... that all the properties in a referenced class are available in the code completion box, within the context of the bean that references the class:
That's definitely my favorite Spring feature in the IDE. So, if you go to the "com.sun.swingset3.SwingSet3" class, which is the referenced class in the screenshot above, you will find methods named "setCurrentDemo", etc. Even better, you can jump via a hyperlink from the above reference to the definition of the setter in the Java class. Very cool and extremely handy. Basically, everything that can be referenced from the Java side is available via code completion and hyperlinks in the Spring configuration file.
Another cool thing is that, since you're dealing with an XML file, you have the Navigator to show you the complete breakdown of your Spring configuration file:
The best enhancement I can imagine would be... a visual view. Some kind of designer that gives you a graphic view on top of the XML tags...