Silverlight plugin & last version of firefox

Hi,
as I don't know where to post (there is no silverlight newsgroup ?), I post
here so don't blame me plz.

With firebug activated, loading the
http://www.microsoft.com/silverlight/#4_0 site, it shows a javascript error
:
Bad NPObject as private data!

I've got the issue with lot of silverlight web sites, so I suppose it's
plugin related, or maybe firebug is causing the bug.
I use firebug version 1.1.0b10

Without firebug there is no error, so it seems it's it.

SL.
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web tools and games


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