Windows 10, i7, NVIDIA 980 TI. Trying various settings under options, re-starting software, etc. I can't get a resize cursor in any of the windows, time line, preview, etc. I can't even resize the height of the tracks.
I have Vegas Pro 12 also (not about to pay $250 upgrade so figured I'd try Studio because I have a version of that too). Anyway, Vegas Pro 12's edit windows resize on this machine.