Right now, in the stable release, the pause menu background has a black tint on it, while in the preview it has been removed.
To make sure players can notice the game is actually paused or tabbing out, other than the text message at the bottom, there should be a pause menu background blur, that also can be adjusted/disabled in the accessibility menu, like on the latest Java Edition has right now.
Java:
[media]
Bedrock:
[media]Linked issues
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Comments 5

Confirmed on Windows. Now that pausing actually pauses the game, blur effects like these should be added without hindering gameplay.
Thank you for your report!
After consideration, the issue is being closed as Working as Intended.
Please note, that mechanics of the game may change between updates.
Things such as graphics, sounds, world creation, biomes, redstone, villagers, and animals may not work the same in current versions.
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