xdg-menu is described as 'XDG-Menu is a ROX panel applet that displays an applications menu button. The menus it builds fit the XDG Menu Specification published by freedesktop.org'. There are six alternatives to xdg-menu for Linux. The best alternative is MenuLibre, which is both free and Open Source. Other great apps like xdg-menu are AppEditor (Free, Open Source), lxappearance (Free, Open Source), obmenu (Free, Open Source) and obconf (Free, Open Source).
LXAppearance is the standard theme switcher of LXDE. Users are able to change the theme, icons, and fonts used by applications easily. It also includes support for configuring openbox, via a plugin called lxappearance-obconf.
uxdgmenu is an automated XDG Menu system for alternative Linux window managers. It supports currently Fluxbox, Openbox, Awesome, Blackbox, WindowMaker, FVWM2, IceWM, Ion3, PekWM, TWM, support can be added to any other through plugins.