I'm using CS5, and for some unknown reason a few weeks ago a line started appearing around elements in my photoshop files - whenever I click on any layer in a .ps document, the perimeter of that layer is outlined. I figured out that I can type Command+H to make it disappear, but it only happens for that moment. The next moment when I click on another layer, the outline appears again, and it keeps appearing for any layer I clicked on (including the one I had just previously high Command+H for). Why? It is very distracting?