It is actually pretty easy.
However, since in this thread, yet another poster has expressed a desire for a larger Grab Area to resize windows on Zorin Lite; I have decided to expand the Zenith themes to include an XFWM4 theme for Zorin Lite (Zenith is a Zorin-like Theme made to accommodate Cinnamon Users wishing to use ZorinThemes).
I will make these themes with smooth Rounded Corners, so any of you that wish, may have an option for that pre-made for you in Zenith.
Generally, the same as Gnome. XFCE, however, like most other D.E.'s has a Window Manager which gnome lacks. Gnome relies solely on the .css file to render the borders, instead of a Window Manager.
XWM4 is written in C and GTK.