Rated 5 out of 5 stars

If anyone is interested here's how you can mimic Opera gesture behavior in FF:
http://www.stefant.org/web/computer/patches/mozilla.html
The scripts here enable you to assign hybrid (context-sensitive) gestures for certain commands. For example you can have the action Down perform "open a new tab" if no link is present and perform "open in foreground tab" if a link is present. Similarly the action Down-Up can be set to "duplicate tab" if no link is present and "open in background tab" if a link is present

This review is for a previous version of the add-on (1.7.2.1-signed).