Yes, this extension is effectively a symptom of what is wrong with Firefox. Rated 5 out of 5 stars

I entirely agree with the comment by 4edrtcghv on January 30, 2011 : This extension is a symptom of what is wrong with Firefox. Yesterday I installed FF4, and since then I already had to set up (now the 3rd) new extensions, because some stuff have been removed from about:config (and I wanted to avoid this ugly orange button...) - browser.tabs.tabMinWidth and browser.tabs.tabMaxWidth have been removed... I had to install a new ext... And now, Holly S... I have install another one just for getting ride of this new tab button... So thanks for the creator of it, yes of course :-) But Firefox starts really to get on my nerves, I mean almost... wonder if I will not reinstall FF3.6.15... it's getting to this far ! My rating is 5 for the add, but FF4 gets a 3. Reactivity is good, yes, but what the f... about removing basic inbuilt functions ??? I suggest you read the above mentioned comment... It clearly explains the problem !!! Had to spend quiet a while on the net to find the proper answers to this general mess, when before it took me maximum 5 minutes to apply my preferences in about:config !