I have a Droid X running version Android 7.0 Configuration I15.MOT.XT1650.0. I think at a system update point, but not sure, a floating dot, grey in color, from dark grey on the outside rim to light grey in the middle, appeared. It is on almost every application screen. I can move the dot around on the screen. If I touch the screen in the "wrong" way, or tap the dot, the screen is replaced with concentric rings of application icons, along with about a third of the screen devoted to ads. As a general question with respect to Android, how do I find out what app is doing this using settings or some tool? As a specific question: How do I get rid of this?