This is an easy-to-use FF extension and I really like it. However, I had to deduct two stars because settings can neither be saved nor restored.

PS: Version 2.3 fixed the issue I mentioned above. It's a five-star extension for me now. Well done.

PPS: I'm sure this extension would become increasingly popular if it were compatible with Firefox for Android. Users would be able to use it on both their laptops/desktops and on their mobile Android devices.