icedtea+firefox crash closing tab

[barbara]

On CURRENT, I've built java/openjdk6 WITH_WEB and all my ports are updated.
After creating the link, IcedTea seems working but if I close the tab or the window on which the applet is running, firefox crashes.
This is happening regularly going for example here:
http://www.javatester.org/version.html
http://www.java.com/en/download/help/testvm.xml

As far as I can remember, the same happened on 8-STABLE, when I tested it few days ago.

Here you can find a backtrace:
http://pastebin.com/sm40fGCk

Ask if you need more details/tests.

Thanks
Barbara