Hi. My layer settings keep changing by themselves. I will open the layer window, give my desired work layer a green check and make it visible. I then make all the other layers invisible. Usually I close the layer window, but sometimes I leave it open. Often, when I start working, the work layer changes itself. Sometimes I get a message saying I am working on an invisible layer. If I left the layer window open, I can see the green check mark pop from the layer I selected to another layer. Why is this happening, and how can I stop it?