Adds 1 pixel worth of padding to the top of the tab bar. Why is this useful? When maximized, and if used with a theme that places tabs on top (such as chromifox - ), and a window manager (such as awesome - http://awesome.naquadah.org/) or extension that removes the titlebar, the tab bar will be positioned at the top edge of the screen. When combined with an extension that assigns actions to tabbar mouse clicks (such as Tab Mix Plus - ), you can, for example, close the current tab by simply throwing your mouse up and middle-clicking, without having to stop and think about positioning.

For more information, see: Fitts's Law - http://en.wikipedia.org/wiki/Fitts's_law