Also saw this post:
http://www.zimbra.com/forums/install...tml#post154649
and specifically this piece of it:
a bug was already logged for mozilla-labs-prism at
https://bugzilla.mozilla.org/show_bug.cgi?id=492110.
Please take a look and vote for this bug. Thanks.
I did, but there does not look like there is very much action on this bug