It works with Sea Monkey too Rated 4 out of 5 stars

just add a target app to the install.rdf for it. Mine looks like this:

<em:targetApplication>
<Description>
<em:id>toolkit@mozilla.org</em:id>
<em:minVersion>1.9.0.*</em:minVersion>
<em:maxVersion>1.9.3.*</em:maxVersion>
</Description>
</em:targetApplication>

This review is for a previous version of the add-on (1.1).