Alt + Tab on PC makes you leave servers and realms

Mojang, please fix alt tabbing! Im a builder on a private server with a bunch of friends and I spend most of my time making redstone contraptions to automate my base and sometimes I need to alt-tab to look at a website guide for a machine I forget how to make, but even in windowed mode it will just randomly decide to leave a server/realm when I alt-tab, and it's especially egregious on fullscreen. Please fix this so we can quick swap to look at guides! I don’t always have access to a second screen, and being able to alt-tab is a necessity!