Edit: As of the 2010-08-26 nightly, this hack seems to have stopped working. I’ll let you know if I find a new solution. It should still work with beta 4 though.
Firefox 4 beta has moved the tabs up above the navigation bar, but not all the way up in the title bar where Chrome and Opera both have put them.

Firefox 4 beta

Opera 10.6

Chrome 6 beta
The hack
Now, the Firefox developers seem to be working on a fix for this, but in the mean time there’s a quick hack which lets you do this right now in your Firefox 4 beta.
First, locate (or create) your userChrome.css file.
Then add the following code:
position: fixed !important;
}
#navigator-toolbox[tabsontop="true"] #TabsToolbar {
padding-left: 109px !important;
padding-right: 150px !important;
padding-top: 0px !important;
}

This will make the tabs go all the way to the top of the window, which makes them very easy to target with your mouse when the window is maximized. (Since it doesn’t matter if you push your mouse outside
the screen.) However, this means you can’t grab the window above the tabs to drag it. You can still grab it to the right of the tabs though. With the code above, there will always be an area next to the minimize-maximize-close-buttons which you can drag.
If you like, you can move the tabs 2 pixels down from the edge by changing the padding-top value to 2px. (Or 3 pixels. Or 4. Or 5. Or 200. But that might not be optimal.)
Also, if you want to make the tabs slightly narrower (to give you more draggable area) you can add this to the userChrome.css file:
max-width: 180px !important;
min-width: 50px !important;
}
Hope you found this as useful as I did. Thanks to Gdgtry for the original code!




