Never knew about that trick, 6Grand. In PSE10, I put the paper on a new blank
layer; click on the move box, then grabbing the left corner push it diagonally inward. Do the same on the bottom right corner. Since the bottom layer is transparent - it has squares on it that you can use to line up the edges to make sure it even all around. I usually leave 2-3 of the squares visible to make the page about 1/4" smaller.
BTW, you can still do this if you have the background paper in the stack already. Make sure the background paper has a transparent layer beneath it. Then click 'the eye' in the layer box off - next to it. Then you can see when you adjust the the next paper layer above it.