I'm using Debian Stretch LXDE (OpenBox) in a dual monitor setup. I activated the openbox context menu of my second screen by setting
Desktop (right click) -> Desktop Preferences -> Advanced (Tab) -> Show menus provided by window managers when desktop is clicked (Checkbox)
My 1st screen context menu appears as it defaults.
So how do I activate the OpenBox context menu on the 2nd screen?
I already tried to figure out some settings in /etc/xdg/openbox/... but with no clear results.
Edit
To clarify my problem: Every screen has its own settings, available by Desktop (right click) -> Desktop Preferences per default. As soon as I activated the window manager context menu the Desktop Preferences disappears and I can't undo my settings.
Edit (2017-12-05)
Left screen desktop context menu

Right screen desktop context menu

The setting caused the right screen desktop context menu, originally made on the right screen desktop

menu.xml)? Or the window-list menu of Openbox? Also it might be helpful to see yourrc.xml.