The launcher does not respect its own default setting to close on game launch; It's still running as a background process, consuming massive CPU resources. As well, if the option to leave it open is checked, it still consumes just as much resources. Closing it manually using the X button has no effect (see first sentence).
"Close" means close.
Comments 3
Sorry, I didn't know there was an about tab. This is the launcher version:
LAUNCHER
2.1.7614
Friday, September 20, 2019, 09:01:53
2e83c57f8b563ebaeb91d0b55692431f4e362183
What exactly do you mean with "Minecraft Launcher 545"?