The Nitrogen window decoration is a fork of the oxygen/ozone 
decoration that allows notably to:
 
 - resize window borders, 
 - change buttons size,
 - hide the horizontal separator.
 - select different title bar blending and frame border size depending on 
   the window title or name, in order to have better integration of GTK 
   based windows in the decoration style.
 - add a size-grip handle in the bottom-right corner of windows. This is 
   particularly useful when the no-border option is selected.

WWW: http://www.kde-look.org/content/show.php/Nitrogen?content=99551