Two days ago I noticed there were rulers on my desktop, one at the top and another on the left which I did not install. The rulers are light gray, about 1/8-inch wide and immovable. They appear to have something to do with the position of any open window because you can see the markings on the ruler move when I reposition a window. If I stop moving windows they fade away in about 5 seconds. I have multiple monitors but the rulers only exist on the primary monitor. I selected another monitor as my primary and the rulers moved to the newly selected primary monitor. I've done a cold reboot, checked programs and apps for 3rd party software I didn't install and changed my background theme but to no avail. I've searched and cannot find anything related to this issue. I would like to remove these, so I would appreciate any suggestions.