A family of Microsoft word processing software products for creating web, email, and print documents.
Well, that is certainly disappointing. I've noticed Excel does the same thing. Also, it doesn't strictly adhere to the order they were edited.
In the example from the question, while manuscript #3 was the most recently edited document, manuscript #2 was not the second; manuscript #1 was the second most recently updated. Very curious that document windows just rearrange themselves will.
It's just such a weird phenomenon, given that other programs do not do that. For instance, if I have multiple Google Chrome windows open, they stay in the order they were opened, rather than rearranging at random.