Rated 4 out of 5 stars

I like this, its very useful..... BUT....

I keep dragging it out of the Add-On bar, and when I re-open the browser, it goes back to the bottom...

I do not like anything on the add-on bar, it's an unnecessary bar, most people don't like all these toolbars... please get it to where it stays where its moved...

This review is for a previous version of the add-on (0.6.1-signed). 

Agreed..... BUT....

I've never had it in the add-on bar, as I also don't have that bar visible. See https://bugzilla.mozilla.org/show_bug.cgi?id=586029 for why I have no say in where the icon is put, otherwise I wouldn't put it there.
I moved it to the Titlebar for myself, as you can see in the screenshot I uploaded for it, and it stays there for me across restarts.

The moveability of the icon is totally dependent on the underlying add-on kit which this add-on uses, so please file a bug with the maintainers of it at https://bugzilla.mozilla.org/enter_bug.cgi?product=Add-on%20SDK

There is hope in https://bugzilla.mozilla.org/show_bug.cgi?id=695913 for having icons in the navigation bar, and if by process of elimination you discover another extension triggers this bug, we can inform that extension's author.
I'm sorry about the formatting of this reply, the form doesn't allow clickable links, and thanks for the review, I appreciate it :)