Comment 3 for bug 290492

"activate_window_menu" is unrelated to the window menu coming up with alt+right click. The text is not incorrect. On my system, disabling "activate_window_menu" makes no difference to alt+right click. If it does on your system, that is a bug.

I suggest you change "/apps/metacity/general/mouse_button_modifier" to some other modifier, such as "<Super>" for the Windows key.