I have some code that has several panels one panel holds a button that you press to play a sound file. Another panel holds a tree. When you click on something in the tree I am having it change the value of "filename" which is defined at the top of the class. It's doing its println of filename, so I know it is doing the right thing when you click on the tree nodes, but the file that plays is still the old audio. How do I tell it to refresh?