Upvoted as well. This also causes my client to disconnect from an official Realms server when I alt tab. Not as bad as disconnecting all players on a LAN server, but still very annoying. There are lots of other games in the Windows Store that don't have this issue. I'm not sure if those games are actually UWPs or just Win32 Store apps, but either way, there's no reason this should still be an issue for Minecraft.
Mitch Lindgren
Upvoted as well. This also causes my client to disconnect from an official Realms server when I alt tab. Not as bad as disconnecting all players on a LAN server, but still very annoying. There are lots of other games in the Windows Store that don't have this issue. I'm not sure if those games are actually UWPs or just Win32 Store apps, but either way, there's no reason this should still be an issue for Minecraft.