Thanks, I finally found that option - Could you make it so that this becomes an option in the context menu when you click on the taskbar options? I swear I looked through the options menu 3 times before and couldn't find the relevant option. I would have hoped for a "restore window" button.

About the stuttering: I'm playing on a laptop and my display gets drawn by the integrated graphics card, but games load in the dedicated graphics card. This might prevent some of the interference.

I don't know about CPU use - I'm playing major potato mode to get 40 FPS, so maybe I should rather turn it off.