Rated 5 out of 5 stars

Very good addon!
Thank you!

For use on 3.x:
1) rename "composertf-1.0-tb.xpi" to "composertf-1.0-tb.zip"
2) unpack file "install.rdf" from this archive
3) Open it in notepad, find string "<em:maxVersion>2.0.0.*</em:maxVersion>" and change to "<em:maxVersion>4.0.0.*</em:maxVersion>".
4) save this file.
5) add it to arhive "composertf-1.0-tb.zip" (replacing original).
6) rename back "composertf-1.0-tb.zip" to "composertf-1.0-tb.xpi".
7) instal it. (it must work)

I use this addon on 3.1.10 all are OK!