Related to the 'Secrets of the NetBeans Window System' discussed yesterday, there are many more little "secrets", all described in this document. There's really a lot of tweaking you can do to the window system to make it fit your requirements. Some are useful, while others are potentially quite funny.
How about 'netbeans.winsys.imageSource', for example. I created a module, popped an image into it and then installed the module. Then I put this into 'netbeans.conf', as one of the 'netbeans_default_options':
The value of the above line points to the location of the image within the module, using the complete module path to get to its location. And then what happens? Check it out:
The empty document area, as you can see above, is no longer empty. This has some undesired side effects, but it is fun. Read more about this and other similar tweaks in this document.