I was having the same issue and contacted SU support. I’m on Windows 10 and had my display setting at 125% scaling (older eyes). I reset the scaling in the windows display setting back to 100% and regained the full area of the workspace window.
I also updated my Nvidia driver, rebooted, etc. I’m using an Nvidia Quadro 2000 graphics card, which I’m guessing is now about five years old.
SU 2022 does not have the same issue; it seems to be a 2023 problem.