That removes the compiler error, thank you. Also works to use ViscoSimGUI.class .
I am trying to think why -- maybe this was referring to an instance of the class when it needs to refer to the class itself here. However I still don't see why the API overview's example would work, or some other examples I see on the web.
I just tried taking off the "extends JFrame", also removing the constructor...I don't know what is different in mine.