Just use fake fulsscreen mode aka maximized window without any decoration. Openbox works just fine with that. I dont even notice that it is window because it maximizes automatically.
just paste this into .config/openbox/rc.xml
code>
application name="spring">
fullscreen>yes< slash fullscreen >
/application>
code>
SAD
Openbox is best non tiling window manager try it. For example in shitty metacity I cant make with mouse wheel scroll up window on top or make clicking wheel on desktop to show up all open windows that makes using 4 desktops such pleasure. openbox rulz!