Transparent JDesktopPane with intransparent JInternalFrames?

Hello,

I was wondering: If a JDekstopPane is made transparent
eg:
JFrame jf = new JFrame("Frame");
jf.getContentPane().add(new JDesktopPane());
AWTUtilities.setWindowOpacity(jf, 0.75f);

Is it possible to have intranparent (or less transparent) JInternalFrames? AWTUtilities.setWindowOpacity only applies to Windows...

Imho this could be difficult, 'cause SwingCompnents are lightweight-Components and a DesktopPane / InternalFrame does not have a corresponding awt class)

Is there a way to not draw the JDesktopPane's backround (via some paint (Graphics g) magic - for instance) and use an underlaying JWindow for the opacity-effect? Furthermore, how can I prevent painting the Pane's background?

Thanks in advance,
Keep smiling
yanosz
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