Didn't you do such a workout in your application, Java Tip. This is the first time such a thing comes into my mind.
I am aware that both netbeans and eclipse have such features. I am developing a robotics IDE in my free times. For now, i am concentrating on the core of the system and making it as generic and simple as possible, In the future, i will either use netbeans/eclipse platform or continue with custom swing application way. No matter what i choose, i am sure i will make it a plugin based application. It is useful.