How do I enable the globalmenu / appmenu on Xfce or LXDE?

PPA method

• Add the following ppa ppa:the-warl0ck-1989/xfce-appmenu-plugin

sudo apt-add-repository ppa:the-warl0ck-1989/xfce-appmenu-plugin

• Install

sudo apt-get update && sudo apt-get install xfce4-appmenu-plugin indicator-appmenu appmenu-gtk appmenu-qt

• Right-click on an empty part of the top XFCE panel and choose Panel > Add New Items > App Menu plugin

Manual method

1. Install the missing dependencies. In a terminal : sudo apt-get install indicator-appmenu appmenu-gtk appmenu-qt

2. Install the app menu : download this deb and open it with the software center

3. Enable app menu for firefox and thunderbird. In a terminal : sudo apt-get install appmenu-gtk3 firefox-globalmenu thunderbird-globalmenu

4. Right-click on an empty part of the top XFCE panel and choose Panel > Add New Items > App Menu plugin

Source