GUI-Editor Palette Extension not working?

I tried to extend the GUI Editor with a standard Swing component with the following File:
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The file Showed up in the GUI-Options-Dialogue and i chose it and restarted IDEA. Bu no matter what I did (I even copied the rt.jar from the JDK to the IDEA lib dir because the doc says the Component jar should be there) the palette never showed up.

Has anyone an idea what went wrong? Did anyone try to integrate Stadard Swing components into the Editor?

cheers
roman