With Firefox 3.5 Released yesterday, many unsuspecting users are going to unwillingly discover the new tab tearing ‘feature’ in Firefox 3.5. This ‘feature’ allows you to tear a tab from the current window to have it opened in its own window. The problem with this is simply clicking on the tab and dragging it downward tears it from the current browser window and places it in another new window.
Personally, I have never seen (or had) a practical use for this ‘feature’ and have found it to be more of an annoyance since it was introduced back in the 3.1 developmental builds. I have always wondered if I was the only one who disliked this ‘feature’, apparently I am not. Back in June 2009, WhiteAlice0775 created an add-on named bug489729 (this is one of the bug #’s which people complained about this ‘feature’) which gives you the ability to turn off the tab tearing ‘feature’.
Note: This add-on is presently marked as experimental. You do NOT need an AMO login to install this add-on. Simply check the box beside ‘Let me install this experimental add-on’ and you will be able to install this add-on as you would normally. After you have installed and restarted Firefox, go to your add-ons manager and click Options on bug489729, place a check in the boxes and click OK. Setting take effect immediately.
bug489729 is for Firefox 3.5 only and is about 5 KB
Source: Mozilla Links