How to keep 4:3 aspect ratio?

[Geniusssmit]

I found the game that is 4:3 640x480. When I try to use Borderless Gaming on it, game terribly stretches to match my 16:9 screen. How can I force Borderless Gaming to keep original aspect ratio?

[cjrobe]

Same issue here. Trying to run Touhou 7 in fullscreen and it stretches it to 16:9. It would be really great if the Borderless Gaming Devs could have the app respect ratio, and add a black border behind the game.