To save screen space, Ubuntu Unity uses Mac OS X style global menu that integrates applications’ menu bar into the top panel.
How to install TopMenu plugin for XFCE:
For (X)Ubuntu 14.04, (X)Ubuntu 14.10, (X)Ubuntu 15.04, and Linux Mint 17/17.1, this Xfce plugin is available in the webupd8 PPA.
1. Open terminal from the application menu. When it opens, run command to add the PPA:
sudo add-apt-repository -y ppa:webupd8team/mate
2. Update system package cache, install “xfce4-topmenu-plugin” as well as other extra plugins.
sudo apt-get update sudo apt-get install xfce4-topmenu-plugin libtopmenu-gtk3 libtopmenu-qt topmenu-mozilla-extension
3. After installing this plugin, you have to restart Xfce session by logging out and back in to load the Topmenu modules.
4. Finally, right-click on panel and navigate to Panel -> Panel Preferences. Under items tab, add “TopMenu” and change its position.
For issues, please reports to gitorious.org/projects/topmenu/issues