Oh fuck me sideways, now I understand. And hate it more. I have not, and will not, update my home computer to this nonsense. Foolishly, I updated my work laptop though. Now, the vast majority of times I grab a corner to resize, even when I get the double arrows, it doesn’t resize and instead moves the entire window for some reason. Truly Apple hates us and wants to punish us for loving their products for so long.