One of the most annoying things in my day to day work have been that I can not maximize the current window to it’s vertical capacity. Maximizing over the complete screen was working like a charm. Too bad I didn’t google for the things earlier.
At the obvious place (Openbox wiki) I found the commands ToggleMaximizeVert and ToggleMaximizeHorz.
So I added it to my ~/.config/openbox/lxde-rc.xml