Recently, a "lock object" feature was introduced which is AMAZING, thank you. However, as others have noted, sometimes a whole page is an image (say a form that you're filling out, working with other little images or handwriting on top of it). We're all doing it, I'm sure you don't need a picture. It's great that I can lock the base layer, but still EVEN IF I've already sent it to the back, if I select it, it visually brings it front and now I can't see the objects on top. This defeats most of the benefit of having it locked. If I've sent it back, leave it back, because I can't see what I'm doing now.....