Maybe GOG 2.0 already does this. I'm not in the beta, and no one I've seen talking about it has mentioned this so I'm guessing it doesn't. However, this is a feature I feel is critical prior to release. I've been talking to my friends, and while I'm excited about GOG 2.0 they've all been kinda "meh" about it, especially when they learned they have to keep all their other launchers running.

Now technically I'm sure they just need to be installed, and they'll be launched when the game is launched, but many people don't want those platforms running in the background all the time. It is possible to programmatically catch the launcher/platform process and terminate it after the game's process has been terminated. I feel this will be a critical feature needed for people to adopt GOG 2.0. It certainly seems to be for everyone I've talked to so far. I'd hate to see this new platform launch without it and lose adopters on account of it's absence because I REALLY want GOG 2 to be successful.

There's the option in the settings, not implemented yet.

Awesome, glad to hear it's on their radar at least.

There are options perlauncher so that you can keep some up and close the others, yeah.

Yeah I was glad to see that was the case while poking through settings. I always leave Steam open while opening/closing everything else when needed. Now I leave Steam AND Galaxy open. Honestly if we can get Steam Activity feed integrated into Galaxy, including the posts from followed games, I'll probably just leave Galaxy open.