Exit Minecraft window without a menu?

I'll do an example… If I have 2 Minecraft windows open and one wants to open but the other does not want the menu / inventory or anything else to open. Is that possible?

In the .minecraft folder there's a file with the name optional.txt. There's "pauseOnLostFocus" a little further down.

If you write "false" instead of "true" behind it, you can leave the Minecraft window without opening the menu.

Alternatively, you can press F3 and P and achieve the same effect.

Thank you! I will try it