What’s the tab position in your Firefox? are “Tabs on Top” or on bottom? by default from Firefox 4 onwards Mozilla puts Tabs on Top and they offered the option on Options submenu where user can uncheck and put tabs on bottom again, we don’t know about others we always prefer tabs position on bottom and that’s why we found that option quite useful after installing Firefox, but now what happened! Mozilla removed Tabs on Top option in Firefox 16 15 Beta, Mozilla might get some criticism for this minor change which  can be similar to some what happened in case of http:// protocol, fortunately they’ve offered the preference in about:config to put the tabs on bottom again.

Disable Tabs on Top in Firefox 15 Beta or bring tabs on bottom

1. Type about:config in browser, agree to the warning

2. Find and toggle the preference “browser.tabs.onTop”value to false and restart Firefox for the changes to take effect.

3. Now you can see Tabs on bottom and Tabs on Top option also back.

Tabs on Top option timeline comparison between Firefox 14 and 15

Let me tell you don’t lose this option if you upgrade from Firefox 14 to Firefox 15 you can still spot it if you reset Firefox 15, but users who perform clean installation of Firefox 15 Beta will know this straight away.