Yes, it's annoying because they changed it. You'd cmd-grab a corner and drag away, and content and frame would resize as the Lord saw fit. And all was good. It's how they did it in Caxton's time.
Simples.
But Adobe then hired a nice young lady. She had great references. OK, she had a tail and horns, but it's the fucking modern times and hey, you know, design hipsters. They're all body modding these days. Don't judge. She'd say perky things like 'why don't you move your software to subscription model, everyone would love that!' and 'I'm punching you in the soul, you just won't feel it until you're dead, which incidentally won't be long from now, maybe, oh I don't know, 5.03pm!' Everyone loved Finestre, of course. Mostly because they wanted their children to just have the one non-swivelling head.
So, yeah, Finestre decided to make the teeniest change. The littlest of little things. But she knew, being The Demon of Such Things, that it would slip a splinter under the fingernails of the unwary. The words would be darkly uttered. Children would cry. Mummy, daddy said that word AGAIN. Because now it's all down to timing. You have to press cmd before dragging. There's no point hitting it any other time, if it ain't down when you drag, then it's mummy-daddy-said-that-word again.