The introduction to the new fresh UI for Java Edition is kinda cool and I really love it. However, it also comes with lots of bugs and problems when switching back to the dirt background (using programmer art resource pack) and enabling high constrast resource pack. Here are the problems

Programmer Art (Classic dirt background)

• Switching back to the dirt background is completely fine. However during the gameplay when you press ESC to pause the game, instead of showing what's going on in my world, it just show a completely dirt background instead and this is kinda annoying. This also happens to some screen like the options screen, advancements screen, open LAN game screen, copy to clipboard screen and more. It should show the gameplay instead of a dirt background

High constrasts (Resource pack)

• (Same with the dirt background). During the gameplay when you press ESC to pause the game, instead of showing what's going on in my world, it just show a completely solid black background instead. This also happens to some screen like the options screen, advancements screen, open LAN game screen, copy to clipboard screen and more
• When you enter an area with a different client light level (like entering a cave), the screen and the gameplay becomes darker for some reason and light blocks like torches, lanterns, etc. or night vision effect just don't work. When you enter the Nether, you can still see things but light level from fire, lava is doesnt work. When you enter the End, you will see nothing, everything is just a solid black until you place some light blocks near you, you'll be able to see things a bit better

For more details of this bug, please take some times to watch this video:

https://www.youtube.com/watch?v=T82G6Avl56M

(Start watching at 5:23 for the bugs)

Thank you and hope the developers will fix these bugs as soon as possible!