So essentially my idea here is for you to be able to lock certain elements and have them count as the background.

Let's say I have a line running through all of my slides, as a design element, and I want it to seem seamless. I'd use slide transitions-- no issue, change them both. But if I want to use a different transition for the stuff ON my slide, the line will move as well, the effect broken.

So, if I could say "this line is part of the 'background,' treat it as such" I could then make full use of the transitions-- and if this were the case, you could lock elements and prevent them from even being selected, which would make super complicated slides a lot easier to work with. Like right now if I lock something, it's "out of the way" but not really. If I had a "lock to background" button where those literally are just entirely locked there, and aren't selectable without unchecking that, it'd clean things up a lot.

Just a thought!