Add support to use several browser windows to mimic/implement a multi-head system with several screen monitors. In a first step would be just enough to use window.open() function and postMessage() to comunicate between main and auxiliar windows (or better, move core functionality to a SharedWorker and windows doing requests to it), and in the long term allow to use windows on several independent devices (smartphone, tablet...) to extend the desktop area or show notifications or for an auxiliar tools panel.
From https://github.com/os-js/OS.js/issues/423