MultiDisplayFullscreen on Linux?

Was wondering if setMultiDisplayFullscreen is actually working on Linux? I tried to use this in Ubuntu 14.04 and the app only covers one monitor when going into fullscreen.
In main.cpp:

ofAppGLFWWindow glfw;
glfw.setMultiDisplayFullscreen(true);
ofSetupOpenGL(&glfw, 3840, 1080, OF_FULLSCREEN);
ofApp *app = new ofApp();
ofRunApp(app);

Do I have to use a specific window manager or distribution to get this working?