Rated 5 out of 5 stars
I tried it out (FF v3.5.5) and it's working exactly as it should.
In order to understand the various options don't forget to check out the developer support page --> menu Documentation.
@vinc17: You don't need to type backspace to clear the current text but left click is needed.
NB for the developer: it would be great not to have to left click in order to paste in the search or address (url) bar.
@Fei Jai: Why to middle click the magnifying glass? Just left click once in the search bar and then middle click to have the highlighted content be replaced by the clipboard content you want to paste... Then press enter or left click know the magnifying glass button.
Except what I've pointed out in above it's a great working add-on. Thanks for the good work!