See http://kb.mozillazine.org/accessibility.tabfocus

Note: In OS X (as of 2005-01), if this preference is not explicitly set, the “Full Keyboard Access” setting in System Preferences will be honored. All builds before that date (e.g., Firefox 1.0.x) will ignore that setting.

I have set accessibility.tabfocus with integer 7. I did this by right clicking on about:config and choosing Integer, then entering accessibility.tabfocus, then entering 7 in the next popup box. Didn't work. I have checked in System Preferences > Keyboard Shortcuts: Full Keyboard Access. Didn't work. I have done both, together. Still didn't work.

There is another accessibility.tabfocus_applies_to_xul;true Should I change this one to 7 as well?

I've deleted the prefs.js file and reloaded the pages, restarted Firefox after every change but I can't seem to tab, for example, Facebook: when I would write a comment and hit the tab button to move to COMMENT box and press Enter and it would post. But now it just jumps from comment box to comment box.

I greatly appreciated your help.

Wow. I was missing a simple input. I went back to the beginning, and started fresh and I was doing all my testings on Facebook's site. Little did I know that if I don't enter anything in the comment box and hit the tab button, it just moves to the next comment box. I entered some text and it worked. I guess I shouldn't use Facebook for testing purposes. Thanks a bunch for your help. Please disregard my reply after your help.

Note: my install of FF 3.6.13 did *not* have a configuration option under: accessibility.tabfocus and hence I had to create one. Works fine now though :)

I cannot understand any of these solutions. Can someone give me a step-by-step method to solve this, in plain English, for someone who is NOT a web developer? When I press tab, an annoying icon bar pops up in front of my window showing all my open windows. I am running Windows 7 on a pc.