You can check the pref browser.tabs.drawInTitlebar on the about:config page.

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.

browser.tabs.drawInTitlebar was set to true. I tried changing it to false restarting firefox and back to true restarting firefox but no change.

I resolved it. Firefox took up the entire screen but was not maximized. When I maximized Firefox, the tabs were in the titlebar. Thanks for pointing me in the right direction (I Googled drawInTitlebar).

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Instead of showing off, why don't you tell us how you got the tabs in the titlebar?

If you maximize the Firefox window then you can get the Tabs in the title bar if you set the above mentioned pref browser.tabs.drawInTitlebar to true.

See also:

• http://userstyles.org/styles/42402 Firefox 4 Normal Window Tabs In Titlebar

Thanks for finding that cor-el!! I have tested it on FF6b3 and it works on it as well!!

You're welcome

Firefox 6b3 is old, you should update to 6b5 (Help > About)

• http://www.mozilla.com/en-US/firefox/all-beta.html