Firefox will not boot and run successfully in any extended screen/desktop mode--only when using the local laptop screen itself. I wiped an older version, but even the installation sequence ran like cold molasses in... Had to drag windows to cause them to refresh, so I could see what options to click. Windows did not appear responsive to mouse clicks. They were, but took minutes to respond. Finally, I tried a Windows key-P and chose Disconnect Projector--and there was Firefox. But back at extended display, Firefox refuses to run.