Photoshop has never allowed the grabbing of the corners of selections, per se...
Is it possible you're talking about resizing placed objects on a new layer? With the Move Tool selected, what is your setting for the following option in the options area?
Or are you perchance talking about Paths?
EDIT: I updated the image above. I originally had the arrow pointing to the wrong option. I meant it to point to the [ ] Show Transform Controls option.
thank you so much, i didnt kno it would be so simple lol this really helps me! thank you!!!!