Firefox will no longer display the main window. I get an icon in my taskbar but the window is nowhere to be found. I've tried the tricks of maximizing it and moving it but neither works. I have found that if I locate the xulstore.json file it will work but only for a short time. Next time I start Firefox I get an icon but no window. Very frustrating! The sulstore.json file contains nothing that suspicious: ``` {"chrome://browser/content/browser.xhtml":{"main-window":{"screenX":"2129","screenY":"777","width":"1280","height":"1040","sizemode":"maximized"},"sidebar-box":{"sidebarcommand":"","style":""},"sidebar-title":{"value":""}}} ``` If I start Firefox and right-click the icon, select maximize it's as if it's maximized covering all my windows but yet invisible. I can see my other windows but I cannot interact with them. Deleting the xulstore.json file often fixes this but it breaks again shortly. What's the deal???