Rated 4 out of 5 stars
Does not work in Nightly 21This review is for a previous version of the add-on (3.7.1-signed).
I tested Scroll To Top on Nightly 21.0a1 (2013-02-12), and it is working absolutely fine. May be some other plug-in is breaking because of which Scroll To Top is also failing..
Can you try Scroll To Top in a separate user profile.