The full-screen option in-game doesn’t make the game, True Full Screen, which is in any other game, even Minecraft Java. The issue is that not having a true full screen can cause you to tab out of the game or click an app in your taskbar, which is very annoying since Minecraft Bedrock disconnects you when tabbing out. I will include some screenshots of the issue.
Attachments
Comments 2
This is a feature of UWP apps and not a bug with the game. Mojang would have to change the app type to something else to remove this behavior, which they have recently done in Minecraft Preview. See this article for more information:
As noted in the article, the switch to GDK is also expected to come to the release/full version of Minecraft.
Please edit your report to change the Affected Version to the version shown on the Minecraft title screen