Tabbed Browsing Rated 5 out of 5 stars

Now Firefox is nothing more than a bunch of tabs and one menu button :)

Now for the things I like changed:
1. The toolbar shows in the Add-ons tab and it should stay hidden there.
2. The toolbar doesn't show when the mouse hovers over the Firefox menu or the window minimize/restore-maximize/close buttons in Windows and I think it should become visible.
3. The tab looks like it is part of the page when the background colour is light and it looks like it is bleeding onto the page when the background colour is dark. A line underlining the favicon and page title of the viewed tab along the same path as the line below tabs in the background will visually separate the tab. Also make the colour of this line lighter and not touching the edges of the current tab. This will mildly separate the tab from the page while emphasizing the favicon and the page title. Having said all that, there is an exception that has to be taken into account. Some extensions https://addons.mozilla.org/en-US/firefox/addon/brief/ have interfaces that match beautifully with the tab. I think extensions must be treated differently.
4. There is a blank area showing above when using Vertical Toolbar extension https://addons.mozilla.org/en-US/firefox/addon/vertical-toolbar/

This review is for a previous version of the add-on (2.1-signed). 

All of those issues except the about:addons page should be fixed in v3! For the remaining one, we're tracking it https://github.com/mozilla/prospector/issues/386