This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
If you need only one of those Observer panels in your application, then just create one of them. There's usually no need to go through all that tedious Singleton business when a simple "Observer whatever = new ObserverPanel()" will do.