when using alt+tab, the game exits full screen in order to accomplish this. It'd be nice if it stayed in fullscreen.
I was about to say the same thing, but borderless only works with your native resolution, which isn't always the best option (i.e. I have a 16" 1440p screen but play at 1080p as it gives me a significant fps kick in some maps). Using alt+enter to go back to full screen mode resets to native resolution too, so you have to go to settings anyway.
It's not smooth; if you try to alt tab, it'll result in a small delay of a black screen to transition into bordered/fullscreen. On other games I can alt+tab in fullscreen normally, and alt+tabbing back into the game, it still stays in fullscreen. It doesn't make sense why beam can't allow alt tab without becoming bordered, when games like War Thunder allow it smoothly. It'd just be a quality of life improvement
Apps running in borderless mode like to stay on top of other apps. That can be annoying when alt-tabbing and very annoying if the game hangs
