Mozilla/5.0 (Windows NT 6.1; WOW64; rv:27.0) Gecko/20100101 Firefox/27.0 Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:27.0) Gecko/20100101 Firefox/27.0 Mozilla/5.0 (X11; Linux x86_64; rv:27.0) Gecko/20100101 Firefox/27.0 Reproducible on latest Beta (20131111154639), latest Aurora (20131114004000), latest Nightly (20131113030205). Steps to reproduce: 1. Open the Firefox OS 1.2 or 1.3 Simulator 2. Select the "Disconnect" button Actual Results: The Simulator window remains on the screen, it can still be used (doesn't matter if there are opened apps or not). Starting the Simulator again will open a new window and the first one will be closed. Expected Results: The Simulator window is closed. Note: For Firefox OS device, the disconnect button is working. On Ubuntu 13.04 64-bit, the first window remains on the Launcher, unusable.