Rated 3 out of 5 stars

Still works fine, will not install on FF43 due to signing requirement. Easier icon fix from what I reviewed ages ago:

Download extension to desktop
Open in a suitable programme
Go to folder "\chrome\duplicatethistab.jar\skin\icons\" within archive
Extract icon-large.jpg file to desktop
Rename as icon.png
Place this file into root folder of archive (the one that's got install.rdf file in it)
Install to Firefox.
Should now have an icon under add-ons menu

This user has 3 previous reviews of this add-on.