Title-bar icon for JInternalFrame not working

[Paul Lesneski]

Hello,
I have a JInternalFrame that is refusing to display my own icon in its title bar. I verified that the URL is correctly resolving itself, and in fact, am having no problem using the same icon in my main JFrame window. The code is simple:
setFrameIcon(new javax.swing.ImageIcon(ClassLoader.getSystemResource("PPDI.gif")));
Why would I still be seeing the java cup???
Thanks for any tips!

[Paul Lesneski]

Annoying, java is sometimes.
The better solution was in lieu of setting the icon for each internal frame to simply do this in the constructor of my main window, which tells the UIManager to use my icon for all internal frames that are constructed from then on:
UIManager.put("InternalFrame.icon", new javax.swing.ImageIcon(ClassLoader.getSystemResource("PPDI.gif")));
Although I still don't know why the other code wouldn't work...
Sigh