See How to fix preferences that won't save

That hasn't helped the last ten times I tried. I posted before. I deleted the preferences file, I tried changing the preferences file, I went into about:config and changed the autoHide preference there. No dice. Firefox is not saving my preference for that one thing.

Do you have a user.js file on your system? If you have, it will rewrite the prefs.js configuration. See http://kb.mozillazine.org/Resetting_preferences#Software_that_changes_preference_settings

no, there's no user.js. I tried copying the prefs.js to user.js and editing the user.js file manually, but that didn't work. I tried locking both files, and that didn't work either.

Click "Help" | "Restart with Add-ons disabled". In the next menu which appears, checkmark: "Reset toolbars and Controls". Then click the button called "Make changes and restart".

That worked. I have Adblock, Personas, RoxioNow Player Plugin, TrackerBlock, WebRunner, and XMarks. I'm guessing that one of those must be impeding my tabness?

Webrunner. It's Webrunner.

Thank you for your help. I've contacted Salsita software about how I might be able to fix that problem, hopefully there will be a solution already available.

You're welcome.

Could you please click the "Solved It" button next to the post which solved the problem for you? This will help others searching for a solution to the same question.

Thanks.