Dr0ne2 is my first xfwm4 theme ever which goes best with diehard4 and that GTK you can find here:

http://xfce-look.org/content/show.php/Diehard+4+GTK?content=143443

...but it can be used with some other themes. It is just simple border so that you can move and resize windows easily.
This Dr0ne2 is just another moded version of Thinble Xfwm theme by Simon Friis Vindum

Original Thinable Xfwm is here:

http://paldepind.deviantart.com/art/Thinble-362276066