@noheger what was the allowed area before Tahoe?
If the window had a border that should be the area one can grab, windows rarely have borders these days so I’d would have guessed some allowance in both directions, allowing you to grab just inside or just outside the window.
Well, I’ve checked Windows and two desktop environments on Linux (Gnome and Cinnamon), for all three the resize area is all outside the window with the possible exception of non native apps (electron, Discord for example) which may allow clicking only inside.